Optics and Spectral Investigation in Dy^(3+)-Doped Borate Glasses

Dy^3＋-doped borate glasses （LBLB） with high effective visible fluorescence emission were synthesized. The absorption spectrum and fluorescence spectrum of this glass were measured and analyzed. By using J-O theory, the oscillator strengths for some absorption transitions were calculated according to the absorption spectra. The intensity parameters Ω1 （t = 2, 4, 6） of Dy^3＋ were determined by using a least-squares fitting approach, and the values are 4.04 × 10^-20, 1.30 × 10^-20 and 1.82 × 10^-20 cm, respectively. The root-mean-square deviation δrma was calculated. Under UV light excitation, Dy^3＋-doped borate glasses （LBLB） emit intense yellowish white lights. The excitation spectrum indicates that argon laser is the effective excitation source in Dy^3＋-doped LBLB glasses

Dependence of the emission electric dipole line strength of Eu^(3+) on the composition of lead borate glasses

Lead borate glasses xB2O3+(99–x)PbO+0.5Eu2O3(x=70,60,...,10) were prepared by melt-quenching method.The luminescent properties were characterized with excitation and emission spectra.The emission intensities for 5D0-7FJ(J=0–4) were analyzed to give variation of the relative electric dipole line strengths with the composition of glasses so as to examine the crucial implicit assumption of independent electric dipole line strength on the composition of glass in the Phys.Rev.Lett.2003,91,203903 paper studying l...

Dielectric Properties of Some Borate Glasses

The dielectric constant, e’, and the dielectric loss. e", for some selected lead borate glasses within the frequency band 105 to 107 Hz and the temperature range (20-50)’C were measured. The dielectric dispersion and the dielectric loss absorption bands were observed. the relaxation time, the activation enthalpy and entropy change of the dielectric relaxation were calculated. The results obtained were discussed and correlated to the internal network structure of the glasses studied.

The Fluorescence of Pr3+ in Zinc Lithium Bismuth Borate Glasses with Large Stimulated Emission Cross Section

Glass sample of Zinc Lithium Bismuth Borate (25-x) Bi2O3:20Li2O:20ZnO:35B2O3:xPr6O11, (where x = 1, 1.5 and 2 mol%) has been prepared by melt-quenching technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction. The absorption spectra of three Pr3+ doped zinc lithium bismuth borate glasses have been recorded at room temperature. The observed optical spectra are discussed in terms of energy states and the intensity of the transitions. The various interaction parameters like Slater-Condon, Lande, bonding and Racah parameters have been computed. Judd-Ofelt intensity parameters and laser parameters have also been calculated. The stimulated emission cross section (σp) for the transition (3P0 → 3F2) is found to be in the range 3.12 - 10.43 * 10-20 cm2. The σp values are comparatively large suggesting the possible utilization of these materials in laser applications.

The influence of cation additives on the NIR luminescence intensity of Er~(3+)-doped borate glasses

Er3+-doped 25BaO-(25-x)SiO2-xAl2O3-25B2O3 transparent glasses are prepared with x = 0,12.5 and 25 by a solid-state reaction.The Er-related NIR luminescence intensity,which corresponds to the transition of 4I15/2-4I13/2,is obviously altered with different silicon/aluminum ratios.The Judd-Ofelt parameters of the Er3+ ions are adopted to explain the intensity change in the NIR fluorescence,and the Raman scattering intensity versus the amount of Al and/or Si components are discussed.The spectra of the three samples are quite similar in the peak positions,but different in intensity.The maximal phonon density of state for the samples is calculated from the Raman spectra and is correlated to the NIR luminescence efficiency.

Effect of samarium oxide on structural,optical and electrical properties of some alumino-borate glasses with constant copper chloride

The glass system under study was prepared and examined using the melt quenching procedures and XRD to emphasize the amorphous nature,respectively.Transmittance of the prepared solid glass system was performed by a spectrophotometer in wavelengths from 190 to 1099 nm.Using traditional techniques and standard formulas,the density,molar volume,refractive index,optical band gap and the optical filter characteristics were determined,then the influence of samarium oxide on some properties like the structure and optical,also the electrical properties were dissected.A novel formula was proposed to estimate the refractive index from the optical energy gap.The obtained samples are good optical filters especially the sample that contains 0.8 mol% of Sm2 O3.Also this sample has the utmost density,the least molar volume,the maximum transmittance,least refractive index,the highest optical band gap and the least dc conductivity.

Influence of Fe_(2)O_(3) on the physical,structural and electrical properties of sodium lead borate glasses

The influence of adding Fe_(2)O_(3) at the expense of Na_(2)O in sodium lead borate glasses on the structural,physical and electrical properties have been investigated.Results obtained from Fourier transform infrared(FTIR)spectra indicated that Fe_(2)O_(3) plays an important role in converting three coordinated boron atoms[BO_(3)]to four coordinated boron atoms[BO4].The physical properties such as density and molar volume helped to evaluate the compact structure of the prepared glass samples due to presence of[BO4]groups.The increase of Fe_(2)O_(3)/Na_(2)O replacements led to increasing the microhardness values and decreasing the thermal expansion coefficients of the studied glasses.The increase of Fe_(2)O_(3)/Na_(2)O replacements generally decreased the AC conductivity.That decrease might be due to converting of the three coordinated boron atoms[BO_(3)]to four coordinated boron atoms[BO_(4)].Dielectric constants of the samples might be an indication of the distortion in the coordinated boron atoms.The obtained experimental data indicated the internal structure of glass network and the change of the structure of the samples from three[BO_(3)]to four coordinated boron atoms[BO4].

Investigation ofmodified zinc borate glasses doped with BaO as a nuclear radiation-shieldingmaterial

Background Radiation protection and detection have been a main interest for researchers.The prepared glass samples were subjected to experimental investigations to evaluate their mechanical and attenuation properties.As a consequence,the values of the mass attenuation coefficient,total electronic cross section,the effective atomic number and an effective electron number were determined and utilized to assess the shielding effectiveness of the investigated glass samples.The mass attenuation coefficients of these samples were calculated theoretically using WinXcom program.Purpose Preparation of glass of borate with zinc and barium can withstand shock,heat and corrosion to be used as a radiation shield.Methods Glass samples were prepared by melt quenching technique.Density and molar volume measurements were obtained by applying the Archimedes principle.The hardness was measured by using a microhardness tester(Leco AMH 100,USA)for sample indentation.The thermal behavior of the glass samples was investigated by differential scanning calorimetry(DSC).Also,by using a scintillator detector(1.5″×1.5″NaI(Tl))exposed to ^(232)Th,^(137)Cs and ^(60)Co gamma ray sources with accuracy range 0.12%.Results The investigated glasses have relatively good gamma ray attenuation properties,water resistance ability and thermal stability with increasing barium oxide.So,they can be used in containers for keeping radioactive waste and radioactive sources.Conclusion The changes in the molar volume and density show approximately opposite linear trends.Also,μm is dependent on the chemical compositions of glass samples and energy of gamma rays.Good agreement between the experimentally obtained mass attenuation coefficient values and the corresponding theoretical predictions based on the known WinXcom program was observed.Additionally,the effect of gamma irradiation on this glass is minor because its impact on the hardness values and dissolution rate is extremely small.

Physical, structural and optical studies on magnesium borate glasses doped with dysprosium ion

Intense visible emissions from dysprosium(Dy3+) ions doped glasses became prospective for diverse technological applications. In this paper, physical, optical and structural properties of magnesium borate glasses doped with varied concentrations of DyOwere examined. Such glasses were synthesised by melt quenching method and characterized at room temperature using several analytical techniques.Luminescence and absorption spectra(in the visible region) of as-quenched samples were used to evaluate the physical and optical properties. XRD pattern confims the amorphous state of as-quenched samples. The Fourier transform infrared(FTIR) spectra of glasses reveal various bonding vibrations assigned to different functional groups. UV-vis-NIR spectra disclose eight absorption bands accompanied by a band for hypersensitive transition positioned at 1260 nm(~6 H→~6 F). The values of direct and indirect optical energy band gap of the studied glasses are decreased with the increase of Dyion contents. The photoluminescence spectra of all glasses under the excitation of 380 nm display two prominent emission bands centred at 497 nm(~4 F→~6 H, blue) and 587 nm(~4 F→~6 H, green).The achieved intense luminescence from the proposed glass composition may be beneficial for solidstate laser applications.

Electrochemical response of Nd^3＋ ions containing lithium borate glasses

The present investigation was to understand the electrical properties of 27.5 Li2O-（72.5–x） B2O（3-x）Nd2O3 with x=0.5, 1, 1.5 and 2 glasses. We analyzed the impedance data for a wide frequency range to get inside the conduction phenomenon. The conductivity of the glasses decreased due to the decrease in the mobility of mobile Li~＋ ions. This decrease was due to polymerization of glass network caused by the Nd^3＋ ions. Modulus formalism confirmed that the Li~＋ ions overcame the same barrier no matter whether it took part in the conduction process or relaxation process. Scaling of the electrochemical data showed that conduction process in the ion conducting glasses was composition dependent and not the temperature dependent.

Synthesis and characterization of lithium niobium borate glasses containing neodymium

A series of（90–x）Li2B4O7-10Nb2O5-xNd2O3 glass samples（x=0, 5 mol.%, 10 mol.%, 15 mol.%, 20 mol.% and 25 mol.%） were synthesized using melt quenching technique. X-ray diffraction（XRD）, differential thermal analyzer（DTA）, Fourier transformed infrared（FTIR）, ultraviolet-visible-near-infrared（UV-Vis-NIR） spectrometer and photoluminescence（PL） spectroscopic characterizations were made to examine the influence of Nd3＋ concentration on the physical, structural and optical properties. Various physical properties such as glasses density, molar volume, thermal stability, ion concentration, polar on radius, inter-nuclear distance, field strength, cut-off wavelength, energy band gap and Urbach energy were calculated. The samples were amorphous in nature and confirmed from XRD pattern. The FTIR spectra revealed the presence of BO3 and BO4 functional groups. UV-Vis-NIR spectra exhibited nine prominent bands centered at 353, 430, 475, 524, 583, 681, 745, 803, 875 nm corresponding to the transitions from the ground state to ^4D（3/2）, ^2P（1/2）, ^2G（9/2）, ^4G（7/2）, ^4G（5/2）, ^4F（9/2）, ^4F（7/2）, ^4F（5/2）, ^4F（3/2） excited states, respectively. Moreover, the emission spectra at 355 nm excitation displayed three peaks centered at 903 nm（^4F（3/2）→^4I（9/2））, 1059 nm（^4F（3/2）→^4I（11/2）） and 1333 nm（^4F（3/2）→^4I（13/2））, respectively. Fluorescence lifetime was recorded between 53.69 to 28.43 μs. It was found that varying concentration of Nd^（3＋） ions strongly affected the physical, structural and optical properties of the glass samples.

Sol-gel derived B_(2)O_(3)-CaO borate bioactive glasses with hemostatic,antibacterial and pro-angiogenic activities

Sol-gel borate bioactive glasses(BGs)are promising ion-releasing biomaterials for wound healing applications.Here,we report the synthesis of a series of binary B_(2)O_(3)-CaO borate BGs(CaO ranging from 50 to 90mol%)using a sol-gel-based method.The influence of CaO content in B_(2)O_(3)-CaO borate BG on morphology,structure and ion release behavior was investigated in detail.Reduced dissolution(ion release)and crystallization could be observed in borate BGs when CaO content increased,while the morphology was not significantly altered by increasing CaO content.Our results evidenced that the ion release behavior of borate BGs could be tailored by tuning the B_(2)O_(3)/CaO molar ratio.We also evaluated the in vitro cytotoxicity,hemostatic,antibacterial and angiogenic activities of borate BGs.Cytocompatibility was validated for all borate BGs.However,borate BGs exhibited composition-dependent hemostatic,antibacterial and angiogenic activities.Generally,higher contents of Ca in borate BGs facilitated hemostatic activity,while higher contents of B_(2)O_(3) were beneficial for pro-angiogenic activity.The synthesized sol-gel-derived borate BGs are promising materials for developing advanced wound healing dressings,given their fast ion release behavior and favorable hemostatic,antibacterial and angiogenic activities.

Dielectric Studies on CuO-Na₂O-B₂O₃Glasses

This work is aimed to shed light on the dielectric behavior of CuO containing glasses, since no publications concerning this issue have been presented before. Different glasses in the binary Na2O-B2O3 system were prepared by melt annealing technique. XRD spectra have shown that the amorphous structure is dominant in all glasses containing mixed concentrations from CuO and Na2O. The crystalline phases appeared only in glass free from Na2O. The dielectric spectroscopy is applied to shed some light on the conduction mechanisms in terms of changing both the dielectric constant and the electrical modulus of the investigated glasses. The ac conductivity increases with increasing frequency and decreases with increasing CuO concentration. Both the dielectric constant and dissipation loss is decreased with increasing frequency. Correlated barrier hopping (CBH) is considered an appropriate conduction mechanism results from the increase of frequency.

Luminescent Properties of MO·RE_2O_3·B_2O_3 Glasses (M=Mg,Ca,Sr,Ba;RE=La,Eu,Gd)

17 MO·(8- x-y )La_2O_3·75B_2O_3· x Eu_2O_3· y Gd_2O_3 (MLBEG,M=Mg,Ca,Sr,Ba) glasses were prepared with the conventional high temperature process. The results of luminescent spectra and ESR reveal that there are two valence states for europium ions: Eu (2+) and Eu (3+) in this system. The broad emission band peaking at 430 nm corresponds to the 5d→4f emission transition of Eu (2+) ions,and the sharp emission bands peaking at 592,616,650 and 750 nm correspond to the (() 5D_0)→(() 7F_ J) (J =1,2,3,4) emission transition of Eu (3+) ions respectively. In these boron glass networks,the kind of alkaline earth ions determines the amount of Eu (2+) ions reduced from Eu (3+) ions in air. So,the relative emission intensity of blue light and red light of the glass should be controlled by different alkaline earth ions. The experimental results illustrate that the introduction of Gd (3+) ion can distinctly improve the emission intensity ratios between the blue light and red light of the glass,which indicates that the main process of energy transfer is Gd (3+)→Eu (2+)→Eu (3+) in MLBEG system.

The effect of Nb_(2)O_(5)on fast neutron removal cross section,optical,and structural properties of some calcium borate oxide glasses containing Bi^(3+)ions

Background In recent years,the preparation of transparent glass in the visible region has led to the development of radiation shielding materials with measuring structure and optical properties.Also,the study on the interaction of neutron radiation with matter is important in the field of radiation protection.Purpose Preparation of transparent calcium and bismuth borate oxide glasses containing Nb^(5+)ions can be used as a neutron radiation shield and determine refractive index with different methods for this glass.Methods Niobium bismuth borate glasses with composition 60B_(2)O_(3)–20CaO–(20−x)Bi_(2)O_(3)–xNb_(2)O_(5),where(x is in mol%,0≤x≤10),have been prepared using conventional melt-quenching technique;the structure of each sample was studied by XRD,FTIR,and UV spectra chart analysis.Results XRD and FTIR showed that all glass samples were highly homogeneous and had structured with short-rangeorder/amorphous solids.The refractive index of each sample was estimated by charts of UV–Vis and FTIR,in addition to an empirical method,and we obtained values very close to each other.The refractive index values are relatively high,so this glass can be used in nonlinear studies as well as luminescence characterization.The macroscopic fast neutron removal cross sections(R/ρ)have calculated,for all samples,and the highest value was in sample containing 2.5%niobium pentoxide.Conclusion Bismuth borate glass containing a few niobium pentoxide can be used as a protective shield of neutrons.

Thermal and structural properties of Nd2O3-doped calcium boroaluminate glasses

Nd^3＋ doped CaO-Al2O-B2O3-CaF2 glasses were prepared by conventional melt-quenching technique,and their structural and thermal properties were studied.The amorphous nature of these samples was confirmed by X-ray diffraction（XRD）.The measured density showed an increase with Nd2O3 doping,at the expense of CaO.Raman spectra presented changes with addition of Nd2O3,which indicated that the network structure of the glasses studied presented various borate groups,such as tetraborates,metaborates,ortho-borates and pyroborates units.The N4 values calculated from FTIR spectra revealed that incorporation of Nd2O3 into glass network converted the structural units from BO4 to BO3.From the analysis of DTA curves,we verified that Tg increased with the addition of Nd2O3;it was similar to the behavior caused by modifier oxides in the structure of borate glasses.Besides that,the calculated glass stability Tx–Tg for doped samples presented a decrease if compared to the undoped glass.Specific heat and thermal conductivity did not present significant changes with Nd2O3 concentration,up to 2.30 mol.%.The results of density,DTA,Raman and FTIR reinforced the idea that Nd2O3 acted as network modifier.

Effect of RO (R=Ca, Sr, Ba, Zn or Pb) component on spectroscopic properties of Eu^(3+) in RO-B_2O_3 glasses

Eu3＋-doped binary borate glasses with different metal oxide components RO （R=Ca, Sr, Ba, Zn or Pb） were prepared by meltquenching technique. The fluorescent spectral properties of Eu3＋in these glasses were experimentally studied. The analysis on the phonon sidebands （PSBs） indicated that RO component did not cause obvious change of the electron-phonon coupling constant （EPC）. By inspecting the optical absorption edges it was found that RO could greatly affect the band gap energy, and the glass with PbO component revealed the smallest band gap energy, the glasses with ZnO, BaO and SrO showed similar band gap energy. The optical transition intensity parameters of Eu3＋in all studied glasses were calculated, it was found that for each sample its value of2 was larger than that of 4 and 6, and the sample with PbO component exhibited the smallest2, but the λ values for ZBE, CBE, BBE and SBE were very similar. These results might be helpful for the design of borate glasses.

Boron Oxide Glasses and Nanocomposites: Synthetic, Structural and Statistical Approach

Three different precursors of boron-aqua and glycerol solutions of boric acid and ethanol solution of trimethyl borate were used for the preparation of organic–inorganic advanced materials. The films and bulk materials samples were heat treated at 100, 400, 800？C for 2 h. The hybrid samples were stable and transparent until 100？C. The further increase of temperature to 400？C led to destruction of samples, and at 800？C they were molten. The structural changes during the pyrolysis were studied by Fourier transform infrared spectroscopy, differential thermal analysis, and X-ray diffraction. Details of surface morphology were observed by scanning electron microscopy. The obtained BO_3 and BO_4 groups were identified in the molten materials after pyrolysis. The quantities and order of borate structural units as well as residual carbon in the networks depended on boron precursor type. PVA/PEG/B_2O_3 hybrid materials were proved to be appropriate precursors for synthesizing borate and carboborate glass and carbon/borate glass nanocomposites. To access the impact of the experimental conditions on the structural changes of the nanocomposites, cluster analysis of the IR-spectral data was used as a classification method.

Energy transfer from Tb^(3+) to Eu^(3+) in zinc lead borate glass

In order to sensitize the luminescence of Eu3+ ions in heavy metal glass,zinc lead borate glass samples containing various concentrations of Eu3+ and Tb3+ ions were prepared to study the Tb3+ to Eu3+ non-radiative energy transfer phenomena.Energy level structures of Tb3+ and Eu3+ ions were plotted to show the excitation and energy transfer routes.Efficient energy transfer from Tb3+ to Eu3+ was observed and studied qualitatively in terms of doping concentrations.The sensitization turned out to be less effective than expected.Further studies to characterize the oxidation of Tb3+ into tetravalent state and to examine the mechanism of energy transfer are proposed.

Tailoring effect of Y_(2)O_(3)on water resistance of Na_(2)O-ZnO-Al_(2)O_(3)-B_(2)O_(3)glasses

To explore the improving effect of Y_(2)O_(3)on the water resistance of xY_(2)O_(3)-(100-x)(0.05 Al_(2)O_(3)-0.15 ZnO-0.15 Na_(2)O-0.65 B_(2)O_(3))(x=0,0.7 mol%,1.4 mol%,2.1 mol%,2.8 mol%)glasses,glass structure and ion migration characteristics were respectively characterized by an infrared spectrometer and an electrochemical workstation.X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive Xray spectroscopy(EDS)and inductively coupled plasm-atomic emission spectrometry(ICP-AES)were used to comprehensively analyze the alteration products.The experimental results show that with the increase of Y_(2)O_(3)content,the mass loss per unit area of the glass is significantly reduced,and pH in leaching solution has the same change trend with mass loss of the glass,which indicates the improving effect of Y_(2)O_(3)addition on the studied glass.The content of[BO_(4)]structural unit and dc conductivity of glass increase firstly and then decrease with the increase of Y_(2)O_(3)content,and reach a maximum at x=0.7 mol%.Although addition of Y_(2)O_(3)plays the role in the changes of glass structure and ion migration characteristics,the more important influence of Y_(2)O_(3)is on the glass surface alteration layer.Y and Zn elements are enriched on the glass surface and finally transformed into an alteration layer,moreover,the adhesion between the alteration layers and the glass matrix is enhanced with the increase of Y_(2)O_(3)content,which effectively blocks the further interdiffusion between the water molecules and the glass matrix.