Specific Features of the Induced Absorption Spectra of Fluoroaluminate Glasses Doped with Samarium Ions

The induced optical absorption spectra of -irradiated fluoroaluminate glasses doped with Eu³⁺ and Sm³⁺ ions are investigated. It is shown that Sm³⁺ ions in fluoroaluminate glasses are protector ions contributing to the suppression of induced absorption in the optical absorption spectra of the studied glasses. It is revealed that the induced optical absorption spectra of the glass samples heat treated at T = 583°C contain two absorption bands with maxima at 300 and 480 nm, which correspond to radiation-reduced (Sm³⁺)^–. The concentration of color centers produced by -radiation in fluoroaluminate glasses is estimated. It is demonstrated that prolonged heat treatment of the glass at T = 638 K brings about the decay of (Sm³⁺)^– centers followed by the destruction of the samples.     

FTIR Spectral Analysis of Corrosion Mechanisms in Soda Lime Silica Glasses Doped with Transition Metal Oxides

Hydrolysis kinetics of soda lime silicate glass (SLS) with 75 mol% SiO₂ in different pH solutions was investigated. Fourier Transform Infrared (FTIR) spectroscopy was used to monitor and confirm the proposed corrosion mechanisms on the surfaces of prepared undoped (SLS) glass together with samples doped with one of the first 3d-transition metal oxides (TMO) (TiO₂→CuO) when exposed to an aqueous solution for a short time period. The traditional proposed mechanism of silicate glass corrosion through ion exchange is analyzed in correlation with infrared reflectance vibrational spectra to confirm the suggested mechanism. The effects of transition metal oxides are followed and interpreted.     

UV-Visible and IR Spectroscopic Studies of Gamma Irradiated Transition Metal Doped Lead Silicate Glasses

Lead silicate (LS) glasses of the basic composition PbO 75%, SiO₂ 25% together with samples containing (∼0.1%) of transition 3d metal oxides (Ti→Cu) were prepared. UV/VIS optical analysis for as prepared and after successive gamma irradiated samples were used to shed more light on the structural modifications that occur due to different dopants and different irradiation doses. The UV-Vis. spectral analysis for undoped glass shows induced absorption bands at 205–400 nm which are assumed to be correlated with the base host glass and dopant transition metal ion doped glasses and dose of irradiation. The positions of the bands are observed to change slightly by gamma irradiation due to the combined effect of induced defects from the host base glass or the transition metal added. Gamma irradiation is observed to cause a decrease in the intensities of the IR absorption bands of the prepared samples accompanied by losing sharpness. These features are related to more amorphicity or disorder by irradiation or to the possible changes in bond angle or bond length in the building groups arrangement.     

SiO2凝胶玻璃中有机光学活性物质的荧光特性和热稳定性

有机光学活性物质在ＳｉＯ２凝胶玻璃中处于细颈广体状孔或化学惰性封闭孔内,由于孔的保护作用（笼效应）,其热稳定性提高１００～３００℃。复合凝胶玻璃经１００℃处理后,由于吸附水的大量逸出,限制并减少了染料分子及其与环境之间的相互作用,降低了非辐射跃迁几率,染料的荧光效率成倍增加。     

Color Centers in Sulfur-Doped Silica Glasses: Spectroscopic Manifestations of an SO2 Interstitial Molecule

The photoluminescence spectra of sulfur-doped silica glass upon excitation into the absorption band at 203 nm and a temperature of 10 K are investigated. It is revealed that the photoluminescence band with a maximum at about 420 nm and the photoluminescence excitation band have a resolved vibrational structure. A model is proposed according to which the bands of absorption at 203 nm and luminescence at 420 nm are assigned to SO₂ interstitial molecules that are weakly bound to the glass network (the transitions X ^~1 A ₁ C ^~1 B ₂ and a ^~3 B ₁ X ^~1 A ₁, respectively).     

Acoustic Characterization of Silica Glasses

Acoustic characterization of doped silica glasses with a GeO₂, P₂O₅, F, TiO₂, Al₂O₃, or B₂O₃ dopant having different concentrations is presented. Quantitative measurements were performed with a 225-MHz line-focus-beam scanning acoustic microscope. The acoustic velocity variation due to different dopant concentrations is given. It has been found that the Al₂O₃ dopant increases, but the other dopants decrease, the acoustic velocity as compared with that of the pure fused silica. We have also found that the fractional change in acoustic velocity is greater than that in refractive index for a given dopant concentration.     

Rayleigh Scattering in Silica Glasses

Rayleigh-scattering properties in commercial silica glasses is clarified with relation to their fabrication methods. Fused silica and synthetic silica made by the flame hydrolysis of SiCl₄ (VAD) method exhibit similar magnitudes of scattering, regardless of fabrication method. Synthetic silica made by flame fusion of SiCl₄ exhibits ∼10% lower scattering than other silica glasses. The factors affecting scattering are evaluated based on refractive index dispersion and glass transition temperature (T_g). The results suggest that the difference in Rayleigh scattering is predominantly attributable to the difference in T_g , which is affected by impurities, such as OH ions.     

掺氟氧化锡纳米粉体的制备

以无机盐为前驱物采用改进的溶胶凝胶法制备了掺氟氧化锡的纳米粉末,用TEM和XRD对不同热处理温度的粉体进行了形貌和结晶状态表征,并研究了粉体的特性。     

Infrared Absorption Coefficients of Silica Glasses

The absorption coefficient values of several silicate glasses in the IR radiation range were determined. Four methods were employed in this study: (1) direct transmission by CO₂ laser, (2) direct transmission through ultrathin sections using an IR spectrometer, (3) glass particle dispersions in KBr pressed pellets, and (4) IR reflection spectral analysis. Wide variations in values were observed for some of these techniques. The reasons for the variations were explored, and evidence is presented to support the conclusion that the reflection measurements and the low-power transmission technique yield accurate values. The pellet technique was found to possess too many experimental variables which could not be controlled and gave erroneous data. The damage produced by direct transmission of high-power radiation was severe and introduced effects which gave spurious results.     

Color Centers in Sulfur-Doped Silica Glasses: Spectroscopic Manifestations of an S 2 + Interstitial Molecular Ion

The absorption spectra of sulfur-doped silica glass are investigated under different external actions (laser irradiation, saturation of samples in a hydrogen atmosphere, and thermal annealing). It is found that the absorption band at 400 nm has a vibrational structure. A correlation between changes in the intensities of the absorption bands at 237 and 400 nm under different actions is revealed. Reasoning from analysis of the results obtained, a model is proposed according to which these bands are assigned to an S⁺ ₂ interstitial molecular ion. It is demonstrated that none of the optical centers considered in this work is responsible for the observed ESR signal.     

Spectroscopic and X-ray Diffraction Investigations into the Specific Features of Crystallization of Potassium Niobium Silicate Glasses

The Raman spectra and X-ray diffraction patterns of initial and crystallized glasses of the composition 25K₂O · 27.5Nb₂O₅ · 47.5SiO₂ (mol %) are investigated. It is demonstrated that, upon heat treatment at temperatures in the range 740–900°C, nanocrystals similar in composition to the initial glass precipitate in the glass. The sizes of nanocrystals are estimated with the use of both methods.     

Singular Grain Boundaries in Alumina Doped with Silica

Pure Al₂O₃ powder compact sintered at 1400°C after adding 100 mol ppm of SiO₂ shows grain boundaries that are flat, even across the triple junctions. TEM observations show that these flat grain boundaries are parallel to the basal planes of the grains on one side. These flat grain boundaries must be singular. At such a low SiO₂ concentration and a low temperature, it is very unlikely that any liquid phase is present at these grain boundaries to cause such flat boundary shapes.     

部分稀土掺杂磷酸盐玻璃发光性质分析

磷酸盐玻璃中单掺杂镱（Yb）、铒（Er）、钕（Nd）等稀土元素,对其光谱特性,荧光寿命,低温特性等将产生重要影响。也会改善杂质对磷酸盐玻离性能的影响。     

凝胶法制备熔石英纳米复合陶瓷工艺及性能的研究

对凝胶法制备熔石英纳米复合陶瓷的工艺进行了探讨,并对不同工艺参数下的材料性能进行了分析和对比,讨论了影响材料性能的主要因素,寻求其最佳工艺参数.研究结果表明,用凝胶法可以使纳米相粒子均匀分散于陶瓷基体中,并能方便快速制备熔石英纳米复合陶瓷,纳米相引入后明显改善了材料的烧结性能,增加了材料的密度和强度.     

一种新的微型激光器材料--稀土掺杂玻璃

制得了具有双包层结构的掺Nd^3 和Yb^3 单模磷酸盐玻璃光纤,用中心波长为800nm的半导体激光器件钕光纤的光泵源,在室温下获得了波长为1．053um,输出功率为8．36mW的连续激光输出,用930nm的钛宝石激光泵浦掺镱光纤,也获得了1．067um的激光,研究了Nd^3 ,Yb^3 ,Er^3 离子掺杂四磷酸盐玻璃和氟化物玻璃的发光性能与浓度的关系,以及Yb^3 /Er^3 双掺杂玻璃的发光性能,得到了掺钕四磷酸盐玻璃,Yb^3 /Er^3 双掺四磷酸盐玻璃和掺氟铝酸盐玻璃等几种在微片激光器有应用前景的材料。     

Optical Properties of Silver Halide Photochromic Glasses Doped with Cobalt Oxide

Photochromic glasses having composition (SiO₂)₄₅(B₂ O ₃)₃₅(Al₂O₃)_7.5(Na₂O)_12.5(AgBr), (Cu₂O) doped with (CoO) _x , in which, x = 0, 0.006, 0.02 and 0.07 g were prepared using the conventional melt technique. The amorphous nature of these glass samples was confirmed using X-ray diffraction analysis at room temperature. The absorption measurements in the infrared region of the spectrum were recorded in the wave number range (4000–400) cm^?1. Spectral reflectance and transmittance at normal incidence of the prepared glass samples were recorded with a spectrophotometer in the spectral range 200–2500 nm. Experimental and theoretical densities of the prepared glass samples were measured, calculated and compared. Analytical expressions were used to calculate the real and imaginary parts of the refractive indices. Dispersion parameters such as: single oscillator energy, dispersion energy, average oscillator wavelength, and Abbe’s number were deduced and compared. Absorption dispersion parameters such as: optical energy gap for direct and indirect transitions, Urbach energy and steepness parameter were calculated. Effects of doping with cobalt oxide CoO as a transition metal on linear and predicted nonlinear optical parameters were investigated and interpreted. Experimental results indicate that there is an optimum concentration of cobalt doping around 0.006 g. The optical band gap decreases with increasing doping and causes an increase in nonlinear optical parameters. Doping with cobalt oxide improves the linear and nonlinear optical properties of the prepared glasses.     

介孔氧化硅材料组装纳米氧化锡的研究

采用水热晶化法一步合成了掺杂不同锡含量(以n(Si)/n(Sn)表示)的介孔结构氧化硅(MPS)复合材料.通过XRD、N2吸附-脱附、TEM、UV-Vis等分析测试技术对样品的结构进行表征.结果表明,当n(Si)/n (Sn)=100时,大多数锡以四配位状态存在于MPS骨架中;随锡的含量增加到n(Si)/n (Sn)=50时,MPS孔道内出现晶态SnO2纳米颗粒,并保持了良好的介观有序度和孔结构;进一步添加锡到n(Si)/n (Sn)=10时,更多的纳米SnO2颗粒分布在MPS孔道中,但其有序度遭到一定程度的破坏.     

CdS掺杂Ge-Ga-S玻璃XPS研究

采用熔融-急冷法制备CdS掺杂Ge-Ga-S硫系玻璃,对玻璃的XPS研究表明:玻璃样品中含有Ge,Ga,Cd,S 4种元素,样品的主要成分是GeS2,Ga2S3和CdS;Ge,Ga,Cd,S元素的XPS谱线的位移归因于化学位移和玻璃的结构的共同作用;Cd3d3/2和Cd3d5/2的XPS峰值随CdS含量的增加而明显增强.