Two types of high-purity synthetic silica glasses were annealed with different processes in precision annealing furnace. The thermal stress and structure of samples were analyzed by two types of stress instruments and...Two types of high-purity synthetic silica glasses were annealed with different processes in precision annealing furnace. The thermal stress and structure of samples were analyzed by two types of stress instruments and Fourier transform infrared spectrometer. After being annealed at1 070 ℃ for 6 days and then cooled slowly, optical path difference （OPD） caused by stress in the center and edge of Type III silica glass with a diameter of 150 mm and thickness of 50 mm decreased from 6 to 2 nm/cm. Meanwhile, with the same annealing process, fictive temperature of small-size Type III glass decreased to 939 ℃, and structural stability of silica glass was improved. In addition, after being annealed at 1 100 ℃ for 5 hours and then cooled slowly, internal stress in Type IV silica glass with a thickness of 1 mm was basically eliminated, and its fietive temperature decreased from 1 421 to 966 ℃.展开更多
This paper focuses on the preparation of a new extended set of calibrations of cooling rate(fictive temperature)in fused silica determined by inelastic light scattering and its subsequent use to characterize the local...This paper focuses on the preparation of a new extended set of calibrations of cooling rate(fictive temperature)in fused silica determined by inelastic light scattering and its subsequent use to characterize the local cooling rate distribution in ultra-short pulsed(USP)laser modification.In order to determine the thermal history(e.g.cooling rate and fictive temperature)of fused silica,high-resolution inelastic light-scattering experiments(Raman and Brillouin spectroscopy)were investigated.Calibrations were performed and compared to the existing literature to quantify structural changes due to a change of fictive temperature.Compared to existing calibrations,this paper provides an extension to lower and higher cooling rates.Using this new set of calibrations,we characterized a USP laser modification in fused silica and calculated the local fictive temperature distribution.An equation relating the fictive temperature(Tf)to cooling rates is given.A maximum cooling rate of 3000 K min-1 in the glass transition region around 1200℃ was deduced from the Raman analysis.The Brillouin observations are sensitive to both the thermal history and the residual stress.By comparing the Raman and Brillouin observations,we extracted the local residual stress distribution with high spatial resolution.For the first time,combined Raman and Brillouin inelastic light scattering experiments show the local distribution of cooling rates and residual stresses(detailed behavior of the glass structure)in the interior and the surrounding of an USP laser modified zone.展开更多
基金Funded by the National Natural Science Foundation of China(No.51102088)the Program for Hubei Provincial Department of Education(No.Q20121411)
文摘Two types of high-purity synthetic silica glasses were annealed with different processes in precision annealing furnace. The thermal stress and structure of samples were analyzed by two types of stress instruments and Fourier transform infrared spectrometer. After being annealed at1 070 ℃ for 6 days and then cooled slowly, optical path difference （OPD） caused by stress in the center and edge of Type III silica glass with a diameter of 150 mm and thickness of 50 mm decreased from 6 to 2 nm/cm. Meanwhile, with the same annealing process, fictive temperature of small-size Type III glass decreased to 939 ℃, and structural stability of silica glass was improved. In addition, after being annealed at 1 100 ℃ for 5 hours and then cooled slowly, internal stress in Type IV silica glass with a thickness of 1 mm was basically eliminated, and its fietive temperature decreased from 1 421 to 966 ℃.
基金The authors gratefully acknowledge support by the Deutsche Forschungsgemeinschaft through the Grant Nos.Ho1691/8-1 I Li2713/4-1 | Schm2115/62-1,the Graduate School in Advanced Optical Technologies(SAOT)of the Friedrich-Alexander-Universitat Erlangen-Nurnberg and the QSIL GmbH Quarzschmelze Ilmenau.
文摘This paper focuses on the preparation of a new extended set of calibrations of cooling rate(fictive temperature)in fused silica determined by inelastic light scattering and its subsequent use to characterize the local cooling rate distribution in ultra-short pulsed(USP)laser modification.In order to determine the thermal history(e.g.cooling rate and fictive temperature)of fused silica,high-resolution inelastic light-scattering experiments(Raman and Brillouin spectroscopy)were investigated.Calibrations were performed and compared to the existing literature to quantify structural changes due to a change of fictive temperature.Compared to existing calibrations,this paper provides an extension to lower and higher cooling rates.Using this new set of calibrations,we characterized a USP laser modification in fused silica and calculated the local fictive temperature distribution.An equation relating the fictive temperature(Tf)to cooling rates is given.A maximum cooling rate of 3000 K min-1 in the glass transition region around 1200℃ was deduced from the Raman analysis.The Brillouin observations are sensitive to both the thermal history and the residual stress.By comparing the Raman and Brillouin observations,we extracted the local residual stress distribution with high spatial resolution.For the first time,combined Raman and Brillouin inelastic light scattering experiments show the local distribution of cooling rates and residual stresses(detailed behavior of the glass structure)in the interior and the surrounding of an USP laser modified zone.
