Study on structural relaxation in silica glass

研究石英玻璃中的结构弛豫是开发具有高性能如超低损耗和抗紫外性能的石英玻璃的必要条件。二氧化硅玻璃结构简单，有利于玻璃化转变机理的研究。在这个项目中，我们试图在包括玻璃化转变温度在内的宽温度范围内测量二氧化硅玻璃的各种性质，并阐明了结构弛豫过程及其杂质效应如下：（1）OH或Cl增强了由粘性流动控制的α弛豫，并且还产生了亚弛豫过程。(2)he亚弛豫过程是杂质扩散引起的局部结构变化。(3)I抑制α-弛豫，与OH和Cl相反。根据这些结果，我们已经建立了通过杂质掺杂控制结构弛豫，并开发了以下高功能二氧化硅玻璃。（1）Na掺杂超低损耗玻璃（2）I掺杂超耐热玻璃（3）通过OH掺杂、紫外激光照射和热退火产生的超紫外玻璃

Investigations of structural relaxation in silica glass are necessary for developing silica glasses with high performances such as ultralow-loss and UV-proof properties. Silica glass is also advantageous for studying on glass transition mechanism because of its simple structure. In this project we tried to measure various properties of silica glasses over a wide-temperature range including the glass transition temperature, and have elucidated structural relaxation processes and their impurity effects as follows :(1)OH or Cl enhances the alpha-relaxation governed by viscous flow, and also generates a sub-relaxational process.(2)he sub-relaxational process is local structural change caused by impurity diffusion.(3)I restrains the alpha -relaxation, contrary to OH and Cl.From these results, we have established controlling the structural relaxation by impurity doping, and developed the following high-functional silica glasses.(1)Na-doped ultralow-loss glass(2)l-doped ultra-heat-proof glass(3)Ultra UV-proof glass created by OH doping, UV-laser irradiation, and thermal annealing