Rare-Earth Aluminosilicate Glasses

Rare-earth aluminosilicate glasses of the general formula 20R₂O₃· 20Al₂O₃· 60SiO₂ have been formed for 10 of the 14 possible rare-earth oxides. Two series of "mixed-rare-earth" glasses were also formed (Nd/Er and Nd/Y). These glasses exhibit exceptionally high glass transformation temperatures, moderate thermal expansion coefficients, and refractive indices of approximately 1.65. The glass transformation temperature and thermal expansion coefficients vary linearly with the field strength of the rare-earth ion. No evidence of a "mixed-rare-earth effect" was observed. MAS-NMR indicates that the aluminum ions are tetrahedrally coordinated in at least some of these glasses.     

Thermooptic Coefficients of Soda–Lime–Silica Glasses

The thermooptic coefficients, d n /d T , of two series of soda–lime–silica glasses, 25Na₂O· x CaO·(75 – x )SiO₂ and (25 – y )Na₂O· y CaO·75SiO₂, have been measured. When CaO is substituted for SiO₂, the magnitude of d n /d T passes through a maximum negative value. When CaO is substituted for Na₂O, there is a monotonic change from negative to positive d n /d T . These effects are accounted for by the changes in relative values of the coefficient of thermal expansion and the temperature coefficient of electronic polarizability, Θ. The effect of composition on Θ is explained by the changes in density of various nonbridging and bridging oxygens in the glass.     

碲铌铅玻璃在400～826nm范围内折射率色散

利用椭圆偏振仪对碲铌铅玻璃的折射率进行了研究.研究结果表明:该系统玻璃有高的折射率和小的阿贝数.利用单振子Drude-Voigt色散方程推导出经验公式n2D＝1.046Nfλ20+1.221.     

Dispersion of Thermooptic Coefficients of Soda–Lime–Silica Glasses

The thermooptic coefficients, i.e., the variation of refractive index with temperature (d n /d T ), are analyzed in a physically meaningful model for two series of soda–lime–silica glasses, 25Na₂O· x CaO·(75 – x )SiO₂ and (25 – x )Na₂O· x CaO·75SiO₂. This model is based on three physical parameters—the thermal expansion coefficient and excitonic and isentropic optical bands that are in the vacuum ultraviolet region—instead of on consideration of the temperature coefficient of electronic polarizability, as suggested in 1960. This model is capable of predicting and analyzing the thermooptic coefficients throughout the transmission region of the optical glasses at any operating temperature.     

Third-Harmonic Generation from Some Chalcogenide Glasses

Third-order optical nonlinear susceptibilities (χ⁽³⁾) of some high-refractive-index chalcogenide glasses were evaluated from third-harmonic generation. Compared with oxide glasses whose χ⁽³⁾ has been known, χ⁽³⁾ of the present glasses was higher by an order of magnitude. The addition of selenium drastically increased χ⁽³⁾. The highest χ⁽³⁾ was 1.4 × 10^–11 esu, being comparable with those of high-χ⁽³⁾-organic compounds. Further, χ⁽³⁾ generally increased with increasing density in the present glasses.     

不同氧磷比对磷酸盐包边玻璃性质的影响规律

包边技术是提高大尺寸激光玻璃饱和增益系数的关键技术.采用传统的方法熔制玻璃,研究了P2O5含量对P2O5-Al2O3-B2O3-CuCl-Na2O-ZnO磷酸盐包边玻璃的折射率、热膨胀系数、玻璃转变温度、膨胀软化温度以及化学稳定性的影响.结果表明:当P2O5的摩尔分数为60%左右,玻璃样品具有最高的折射率(1.5220)、最低的玻璃转变温度(352.4℃)、较好的化学稳定性[0.52mg/(cm2·d)]和适宜的热膨胀系数(128.427×10-7/℃),是用作钕磷酸盐激光玻璃硬包边的理想材料.     

Structural,optical, and thermodynamic properties of an LiCa2Mg2As3xV3−3xO12 solid-solution garnet

A series of LiCa₂Mg₂As_3xV_3−3xO₁₂ garnet powders (x = 0, 0.25, 0.50, 0.667, 0.75, and 1) were synthesized using solid-state reaction from mixed precursor powders. A complete solid-solution series was found between the endmembers. Energy-dispersive spectroscopy confirmed the homogeneity of the synthesized garnets. The compositions reversibly melted between 1000 and 1160°C and had low sintering temperatures between 650 and 900°C. Thermal diffusivity, heat capacity, thermal conductivity, density, lattice parameter, thermal expansion, index of refraction, and dispersion were measured from room temperature to 800°C.     

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.     

掺杂氧化物对氧化锌系封接玻璃烧结特性的影响

研究了掺杂不同高价态氧化物对ZnO-B2O3-SiO2系玻璃结构和性能的影响。采用差热分析法、X射线衍射、热膨胀仪和影像式烧结点试验仪等分别对玻璃的各项物理性能进行了测试。结果表明:在ZnO-B2O3-SiO2玻璃系统中掺杂高价态金属氧化物,玻璃的密度略有下降;玻璃的膨胀系数降低明显;玻璃的ΔT上升,可以降低玻璃熔体析晶的能力,提高玻璃封接时的结合力和气密性;XRD结果表明,掺杂氧化物和未掺杂氧化物的玻璃主晶相相同,都为Zn(BO2)2。     

Measurement of stress build-up of ion exchange strengthened lithium aluminosilicate glass

A recently developed nondestructive method was used to investigate the stress build-up in chemically strengthened lithium aluminosilicate glass. We utilized an updated version of the gradient scattered light method, which now enables more precise determination of the depth coordinates, recovering a more detailed stress profile around the knee. The main motivation of the work was to characterize and optimize the development of the knee-shaped breaking point in stress profile in lithium aluminosilicate glass prepared by the Saunders-Kubichan method of one-step strengthening in a mixture of KNO₃+NaNO₃ molten salt bath. In the industry, a two-step process is still commonly used to build such a stress profile; the one-step strengthening will simplify the process as well as save the cost. Compared to previous studies, which used a destructive method based on transmitted light photoelasticity, we found that in the samples ion exchanged for 24 hours, the knee-shaped breaking points were situated two times deeper whereas the case depths were 28% shallower. The measured stress profiles were validated by stress equilibrium and by comparison to Na⁺ ion concentration profiles.     

Extended X-ray Absorption Fine Structure (EXAFS) Study on the local Environment around Copper in Low Thermal Expansion Copper Aluminosilicate Glasses

The local environment around copper in the Cu₂O·Al₂O₃·4SiO₃ and CuO·Al₂O₃·4SiO₂ glasses was investigated using the extended X-ray absorption fine structure (EXAFS) technique. It has been found that each Cu(I) in the former glass is coordinated to two oxygens through covalent Cu(I)-O bonds. This is the primary reason for its low thermal expansion coefficient (∼10 × 10⁻⁷ K⁻¹). In the latter glass, which was made by heating the former glass at 600°C in air, each Cu(II) is coordinated to four oxygens and the bonds are ionic in character, contributing to the increase in the thermal expansion coefficient to ∼30 × 10⁻⁷ K⁻¹.     

掺Er3+碲酸盐玻璃热稳定性的改进

制备了掺Er3+ -TeO2-ZnO-Na2O-Nb2O5和TeO2-PbO-B2O3系统玻璃,测定了玻璃的热稳定性和吸收光谱,在碲-锌-钠多组分玻璃中具有不同的玻璃转变温度Tg和开始析晶温度Tx,按照Hruby's参数HR=(Tx-Tg)/(Tl-Tc);(Tx-Tg)越大则玻璃稳定性越好,在TeO2-ZnO-Na2O系统玻璃中ZnO含量增加则(Tx-Tg)增大,加入少量(小于10%(摩尔分数))Nb2O5,Pb0使(Tx-Tg)变大,玻璃的热稳定性变好.     

Thermal Expansions and Chemical Durabilities of Yttria–Aluminosilicate Glasses Containing Na2O and ZrO2

Properties of glasses in the system Y₂O₃–Al₂O₃–SiO₂ containing Na₂O and ZrO₂ were investigated. The difference between the thermal expansion coefficients (Δα) at temperatures above T _g and those below T _g, microhardness, density, and chemical durability were measured in relation to the Al₂O₃/Y₂O₃ molar ratio. These glasses were found to have a smaller value of Δα than that of a commercial coating glass.     

CaO-Al2O3-SiO2-F玻璃的红外光谱和热膨胀行为

采用传统熔融冷却法制备了CaO-Al2O3-SiO2-AlF3(A系列)和CaO-Al2O3-SiO2-CaF2(C系列)系统玻璃。利用傅立叶红外光谱(FTIR)研究了氟对玻璃结构的影响,使用最小二乘曲线拟合法对第1谱带分峰拟合,并对次强谱带的弯曲振动分类,分析了各组振动与氟的关系。另外通过玻璃的热膨胀行为分析了氟对玻璃软化温度和热膨胀系数的影响。结果表明,氟在A系列和C系列中玻璃的结构变化不大,氟主要与铝生成Al-F键作为网络形成体存在,氟含量最大的A4中生成[AlO3F]四面体和[AlO2F2]四面体;氟含量增加,A系列和C系列的软化温度(Tf)都会降低,而热膨胀系数变化不大。     

R_2O_3(R=Al,B)对含磷硅酸盐乳浊玻璃显微结构和热膨胀行为的影响

采用传统的熔融法制得了含P_2O_5的硅酸盐乳浊玻璃,利用XRD、SEM和EDS等手段研究了玻璃乳浊机理和微观结构,并且讨论了Al_2O_3和B_2O_3相对含量对显微结构和热膨胀系数的影响.结果表明:采用P_2O_5为乳浊剂,可以得到乳浊效果明显的硅酸盐系统乳浊玻璃,玻璃的乳浊是由亚稳分相的不稳分解造成的;用3wt% B_2O_3取代Al_2O_3后,玻璃试样析出少量晶体,第二相颗粒的尺寸变得不均匀,热膨胀系数变大.     

电极材料对高折射钛钡玻璃光学性能的影响

研究了不同材质的材料对钛钡玻璃光学性能的影响,探讨利用电熔工艺制备高钛钡玻璃珠的可行性。结果表明相对于Al_2O_3,SiO_2更易使钛钡玻璃颜色着色。而金属钼能显著降低钛钡玻璃的透过率,在静态试验中明显变黑。而2%含量的SnO_2对钛钡玻璃的颜色影响有限。考虑到实际侵蚀量更低,因此只要熔制工艺控制适当,能实现钛钡玻璃的电熔化。     

印刷具有梯度折射率微结构的硫卤玻璃衍射光学元件的研究

通过一种高效而廉价的显微热极化工艺,在硫卤玻璃中刻印出覆盖可见到中红外波长且具有梯度折射率(GRIN)微结构的衍射光学元件(DOE).研究了显微热极化的主要极化参数(极化电压U)对硫卤玻璃的微观形貌、微结构、衍射效果和梯度折射率的影响规律.在U为0.75～1.00 kV范围内发现了有效印刷GRIN微结构硫卤玻璃的形成区...     

Li2B4O7-Bi2O3-WO3玻璃的光学性能研究

采用熔融淬冷方法制备了(100-x)Li2B4O7-x(Bi2O3·WO3)(5≤x≤20)玻璃.采用比重计测定了玻璃密度,分光光度计测量了玻璃的吸收光谱,V棱镜折射仪测量了玻璃折射率.结果表明,随着Bi2 O3·WO3含量的增加,玻璃样品的密度和摩尔体积增大,而氧堆积密度减小;玻璃的吸收光谱中截止波长逐渐向长波方向移动,玻璃的间接跃迁光学带隙、Urbach能和费米能逐渐减小,折射率增大.光学性能的变化和玻璃网络中部分桥氧转变为非桥氧有关.