Photo-Physical Properties of Stilbine-3 (STB-3) Laser Dyes Embedded in Sol-Gel Glasses

Solid-state tunable dye laser materials developed by incorporation of stable laser dye molecules into solid host matrices like polymers, organically modified silicates (ORMOSILS) and porous sol-gel glasses. These materials have technical advantages such as compactness, better manageability and suitability for field measurement. The recent research work with highly porous sol-gel glasses having good transparency in UV-Near UV region used as solid host for solid-state dye laser materials has attracted a great deal of attention because of its high potential utility than polymers. Two different procedure’s are used for incorpoerating the Stilbine-3 (STB-3) laser dyes into porous sol-gel matrices such as dope or dip methods. In dope method dye is mixed at the sol state and drying is carried out afterward;while in dip method matrix is first prepared and the matrix is dipped in desired dye solution. After preparation of these dye embedded sol-gel glasses we studied their spectroscopic properties of using absorption and fluorescence spectroscopy. Along with spectroscopy properties, the studies for longevity or the shelf life and lasing action of these materials were carried out. Laser dye STB-3 incorporated in sol-gel glass samples shows the same result as in methanolic solution.

Comparative Study of Coumarin-120 (C-120) and Stilbine-3 (STB-3) Laser Dyes Doped in Sol-Gel Glasses

In 1967 the first work in solid state dye laser was performed by doping rhodamine dyes in Polymethylmethacrylate (PMMA) materials. Since then some materials like various types of polymers, co-polymers, poly composite glasses have been used as host matrices for doping different laser dyes. Polymers suffer from limited mechanical and thermal stability. Hence glasses can be the alternative hosts. However, because of high processing temperature leading to permanent destruction of dye molecules, the conventional glass preparation technique is not suitable for the introduction of organic laser dyes. This difficulty can be overcome by introducing the laser dye molecules in sol-gel glass which is prepared at low temperature. Recent work with sol-gel glasses shows that these glasses may prove to be better materials compared to polymeric materials because glasses being hard, best optically transparency in Near UV-UV and Visible region and show better photostability. In this research work we reported, comparative study of the photophysical properties of Coumarin-120 (C-120) belonging to 7-aminocoumarin family having two hydrogen atoms attached to the N atom at the 7-position, with Stilbene-3 (STB-3) in three types of HCl catalyzed SiO2 sol-gel matrices prepared by Method I, Method II and Method III respectively.

IR Spectra Analysis of SiO_2-TiO_2-GeO_2 Gel Glass of CO_2 Laser Transmitting Hollow Waveguide

Both titanium and germanium were introduced into silicon dioxide system by sol-gel method to move its region of anomalous dispersion caused by IR resonance absorption towards the wavelength of CO 2 laser.It is indicated by IR absorption spectra that as the content of SiO 2 decreases in this glass system TiO 2 and GeO 2 tends to exist in their own phases.As for the gel glass with a composition of 40SiO 2·30TiO 2·30GeO 2,when the temperature is below 600℃,germanium atoms exist mainly in Ge-O-Ge bonds.With the temperature increasing from 800℃ to 1000℃, titanium atoms in Si-O-Ti bonds almost transform into Ti-O-Ti bonds.Furthermore,a large number of Si-O-Ti and Si-O-Ge bonds formed when the temperature approaches 800℃,which makes a notable IR absorption band round the wavelength of CO 2 laser.Therefore, sol-gel based SiO 2-TiO 2-GeO 2 gel glass is a candidate material for CO 2 laser hollow waveguide.

Synthesis of RE-Ag,Al-RE-doped sol-gel glass and films for solar cells

The paper dealt with the study of fluorescence properties of sol-gel systems doped with rare-earth ions and co-doped with silver. The general problem for these types of inorganic phosphors was a very low absorbance in the visible range. Therefore, a sensitizer of lumi- nescence of the rare-earth ions should be selected and used. The sensitizer should possess a good absorbance in the visible range and strong interaction with the rare-earth ions. In this study silver ions were selected as the sensitizer.

Development of Modified Glasses by Transparent, Functional Hybrid Sol-Gel Nano-Ceramic Coatings, a Comparative Study

This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.

PHBV/Sol-gel Bioglass多孔材料在模拟生理溶液中的化学反应研究

3-羟基丁酸 -co-3-羟基戊酸共聚物 (PHBV) /生物活性玻璃 (SGBG)是一种用于骨和软骨组织工程支架的新型多孔复合材料 ,本文探讨了 PHBV/ SGBG在模拟生理溶液中的一系列化学反应 ,以及多孔材料在模拟生理溶液中浸泡后的成分和结构变化 .研究结果表明 ,在 SBF溶液中浸泡后 ,SGBG与 SBF溶液的离子交换反应和 PHBV的降解反应使 SBF溶液的离子浓度发生变化 ,并在 PHBV/ SGBG表面形成了结晶态类骨碳酸羟基磷灰石 .

Preparation and bioactivity of sol-gel macroporous bioactive glass

Bioactive glass is well known for its ability of bone regeneration,and sol-gel hioactive glass has many advantages com- pared with melt-derived bioactive glass.3-D scaffold prepared by the sol-gel method is a promising substrate material for bone tissue engineering and large-scale bone repair.Porous sol-gel glass in the CaO-SiO_2-P_2O_5 system with macropores larger than 100μm was prepared by the addition of stearic acid as a pore former.The diameter of the pore created by the pore former varied from 100 to 300μm.The formation of a hydroxyapatite layer on the glass was analyzed by studying the surface of the porous glass by scanning elec- tron microscopy,energy dispersive spectroscopy,X-ray diffraction,and Raman spectra after they had been immersed in simulated body fluid(SBF)for some time,and the porous glass shows good bioactivity.

Crystallization in Pb-Zr-Ti-Si-O gel glass

Materials in the lead zirconotitanate system possess useful and interesting electroopticaland piezoelectric properties.Because the sol-gel method possesses a number of desirableadvantages compared with conventional methods, it has been developed as an importantand potential process enabling the preparation of oxide glasses which are difficult or impos-sible to make by conventional methods.Recently,ZrO2-TiO2 and ZrO2TiO2-SiO2 with ahigh content of ZrO2,and PbO-TiO2 with PbO were prepared by sol-gel process.

Structure and Luminescence Properties of Eu^(3+) Doped SiO_2 Glass Synthesized by Sol-Gel Process

Under different annealing temperatures, Eu 3+ doped SiO 2 gel and glass were prepared by sol gel method, and the structure and luminescent properties were studied with excitation spectra, emission spectra, IR and DTA TG. The results show that the fluorescent intensity tends to get stable when concentration of Eu 3+ doped is above 1 86 % (mass fraction) most water absorbed by the gel was removed at 300 ℃, and that the emission spectrum of Eu 3+ , with peaks at 614, 588, 577 nm, is due to 5D 0→ 7F 2, 5D 0→ 7F 1, 5D 0→ 7F 0 transitions, and the excitation peaks at 318, 362, 380, 393, 412 and 462 nm were observed. These results illustrate that the temperature range of 300～500 ℃ is critical for the structure conversion from gel to glass, and the fluorescence is strongly quenched by water.

Growth of PbTiO_3 crystallites in gel glass and their size effect

The special glass ceramics with ferroelectric main-crystalline phase are very usefullbecause of their good electro-optical effect, excellent high dielectric properties and low therm-al expansion coefficient. This kind of materials has been noticed since the 1960s. Withthe development of ferroelectric nanocrystallites and fine composite technology nowadays, itis desired to get ferroelectric nanocrystallites with better-controlled size and to prepare newcomposite systems. Overcoming agglomeration among ferroelectric ultrafine grains is nec-essary. So it is important in this field to get the ultrafine PbTiO3 grains in situ confinedgrown in glass with better controlled size.

In vitro Mineralization Behavior of the Sol-gel Derived Bioglass/Collegen Composite Porous Scaffold

The porous scaffold of the sol-gel derived bioactive glass（BG） in the system CaO-P2O5-SiO2 was treated with the type I collagen solution. The pore walls of the scaffold were covered by the collagenous network. The in vitro mineralization behavior of the sol-gel derived bioglass/collegen composite porous scaffold was investigated by immersion in supersaturated calcification solution （SCS） at 37 ℃ for different times. XRD, FTIR, SEM/EDAX techniques were applied to analyze the crystalline phases, morphology and composition of the minerals formed on the pore walls of the scaffold. It was found that with increasing of immersion time, the morphology of reaction products on the pore walls changed from the spherical particles of calcium phosphate to the flake-like HCA crystals.

Influence of Reaction Conditions on Sol-Gel Process Producing SiO₂and SiO_2-P₂O₅Gel and Glass

The effect of H2O and the slow thermal annealing on the properties of pure silica (SiO2) and phosphosilicate (SiO2-P2O5) gel-glasses are presented. The monolithic samples have been prepared via sol-gel process using tetraethorthosilicate (TEOS), Si(C2H5O)4 and Triethylphosphate (TEP) (C2H5O)3P(O) as SiO2 and P2O5 precursors. Phosphate incorporates into the silicate network by substituting Si atoms and consequently, we observed changes in structural and spectroscopic properties for these systems. The structures of prepared samples were examined by observed weight loss, XRD and FTIR. It has been found that in the structure of pure silica and phosphosilicate glasses there are formed domains characterized by certain degree of ordering of the units present in their composition, while the structure of pure silica is still amorphous of these glasses. The changing character of domains structure may be the reason of different chemical activities of phosphosilicate glass.

Sol-gel preparation and phosphorescence property of Mn^(2+)-doped zinc boro-silicate glass thin films

Mn2+-doped zinc borosilicate (ZBSM) glass thin films were first synthesized by sol-gel method. In the experiment, a thin gel film was depos-ited onto quartz glass substrates by dip-coating method and then heat-treated to form a Mn2+-doped zinc borosilicate glass thin film. Long lasting phosphorescence (LLP) and photo-stimulated long lasting phosphorescence (PSLLP) were found in the film sample. According to fluorescence spectra, LLP emission spectra, and PSLLP emission spectra, both LLP and PSLLP emissions are attributed to the energy level transition of 4Eg→4A1g from Mn2+. Both the phosphorescence intensity decay curves contain a fast decay component and another slow decay one. The thermoluminescence (TL) spectra show that the sample has two kinds of traps at least and their energy level values are about 0.8 eV and 1.02 eV, which could be estimated by the Randall and Willcins formula. The infrared absorption spectra (IR) consist of characteristic vi-bration bands of Si-O-Si, Si-O-Zn, B-O in [BO3], B-O group, and Zn-O in [ZnO4]. Moreover, image storage and logical operation of the ZBSM film were carried out successfully through an experiment analogues of optical storage.

Sol-gel Preparation Copper-cadmium Halide DopedPhotochromic Glass Coating on Plate Glass

Copper-cadmium halide doped photochromic glass coating on plate glass has been prepared by a sol-gel process. The sample shows reversible photochromic effect. The results of X-ray diffraction （XRD） and infrared （IR） spectrum investigations indicate that the photochromic phase of tile coating is CuBrxCl1-x, solid solution, and that the structure network of the coating is connected with the bonds of Si-O-Si, Si-O-B and Si-O-Al.

Preparation and Characterization of CA-MA Eutectic/Silicon Dioxide Nanoscale Composite Phase Change Material from Water Glass via Sol-Gel Method

This work mainly involved the preparation of a nano-scale form-stable phase change material(PCM) consisting of capric and myristic acid(CA-MA) binary eutectic acting as thermal absorbing material and nano silicon dioxide(nano-SiO_2) serving as the supporting material. Industrial water glass for preparation of the nano silicon dioxide matrix and CA-MA eutectic mixture were compounded by single-step sol-gel method with the silane coupling agent. The morphology, chemical characterization and form stability property of the composite PCM were investigated by transmission electron microscopy(TEM), scanning electron microscopy(SEM), Fourier-transform infrared(FT-IR) spectroscopy and polarizing microscopy(POM). It was indicated that the average diameter of the composite PCM particle ranged from 30-100 nm. The CA-MA eutectic was immobilized in the network pores constructed by the Si-O bonds so that the composite PCM was allowed no liquid leakage above the melting temperature of the CA-MA eutectic. Differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA) measurement were conducted to investigate the thermal properties and stability of the composite PCM. From the measurement results, the mass fraction of the CA-MA eutectic in the composite PCM was about 40%. The phase change temperature and latent heat of the composite were determined to be 21.15 ℃ and 55.67 J/g, respectively. Meanwhile, thermal conductivity of the composite was measured to be 0.208 W·m^(-1)·K^(-1) by using the transient hot-wire method. The composite PCM was able to maintain the surrounding temperature close to its phase change temperature and behaved well in thermalregulated performance which was verified by the heat storage-release experiment. This kind of form-stable PCM was supposed to complete thermal insulation even temperature regulation by the dual effect of relatively low thermal conductivity and phase change thermal storage-release properties. So it can be formulated that the nanoscale CA-MA/SiO_2 composite PCM with the form-stable property, good thermal storage capacity and relatively low thermal conductivity can be applied for energy conservation as a kind of thermal functional material.

Sol-Gel Synthesis of SiO₂-CaO-Na₂O-P₂O₅Bioactive Glass Ceramic from Sodium Metasilicate

Bioactive glass ceramic with SiO2-Ca2O-Na2O-P2O5 composition was prepared by the sol-gel method using sodium metasilicate (Na2SiO3) as silica source. The monolith obtained was sintered at 1000?C for 2 hours after which X-ray diffraction (XRD) analysis showed presence of combeite (Na2Ca2Si3O9) as the crystalline phase. In vitro bioactivity test conducted on the material using simulated body fluid (SBF) showed the formation of carbonated hydroxyapatite on its surface. The material during the SBF test was observed to transform from a mechanically strong crystalline phase Na2Ca2Si3O9 to an amorphous phase after incubation for 14 days indicating that the material was biodegradable. Scanning electron microscopy (SEM) was used to investigate the surface morphology, while Fourier transform infrared (FTIR) spectroscopy facilitated the confirmation of hydroxyapatite (HA) formation. The monolith material obtained may be a good candidate for application in tissue engineering scaffolds.

Preparation of Machinable Bioactive Glass-ceramics by Sol-gel Method

The purpose of this research was to prepare machinable bioactive glass-ceramics by sol-gel method. A multi-component composite sol with great uniformity and stability was first prepared by a 2-step method. The composite sol was then transformed into gel by aging under different temperatures. The gel was dried finally by super critically drying method and sintered to obtain the machinable bioactive glass-ceramics. Effect of thermal treatment on crystallization of the glass-ceramics was investigated by X-ray diffraction (XRD) analysis. Microstructure of the glass-ceramics was observed by Scanning Electron Microscopy (SEM) and the mechanism of machinability was discussed. Phlogopite and hydroxylapatite were identified as main crystal phases by XRD analysis under thermal treatment at 750 ℃ and 950 ℃ for 1.5 h separately. The relative bulk density could achieve 99% under 1050 ℃ for 4 h. Microstructure of the glass-ceramics showed that the randomly distributed phlogopite and hydroxylapatite phases were favorable to the machinability of the glass-ceramics. A mean bending strength of about 160-180 MPa and a fracture toughness parameter K_ IC of about 2.1-2.3 were determined for the glass-ceramics.

New Photoluminescence Phenomena of Ge/SiO_2 Glass Synthesized by Sol-gel Method

New Ge/SiO2 glasses have been synthesized by heating the GeO2/SiO2 dry gels under H2 gas at 700℃. The resulting fluorescence spectra show that this kind of Ge/SiO2 glasses emit strong photoluminescence at 392 nm (3.12 eV), medium strong photoluminescence at 600 nm (2.05 eV) and weak photoluminescence at 770 nm (1.60 eV) respectively. Possible photoluminescence mechanisms are also discussed based on the results of X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS).

氢燃料电池电解质P_2O_5-SiO_2快质子导电玻璃的Sol-Gel法合成

采用Sol Gel法制备了P2 O5 SiO2 快质子导电玻璃 ,用四探针薄层电阻测试仪、XRD、IR等手段对玻璃的电性能、物相结构和组成进行了表征 ,并探讨了质子导电机理。结果表明P2 O5 SiO2 快质子导电玻璃中的强氢键、分子水、结构的不完整性是导致高质子导电率的主要原因。

Sol-Gel生物活性玻璃降解性能及矿化沉积的体外模拟研究

本研究采用溶胶 -凝胶法制备了CaO P2 O5 SiO2 系统生物活性玻璃粉体 ,并通过成型、烧结工艺制成多孔材料 ,样品在体外模拟实验系统中进行材料降解性能研究。通过测量溶液pH值、Ca2 + 浓度及样品的XRD、SEM、FTIR测试 ,认为生物活性玻璃本身发生降解的同时表面有一层类骨碳酸羟基磷灰石生成。