Silica glass samples were given various heat treatments under stress at low temperatures and subsequently their residual stress distributions in terms of retardance were observed using a polarized light microscope, confirming previously reported fast surface stress relaxation while providing more detailed characterization. Retardance profiles of silica glass fibers heat‐treated under a constant bending strain in the presence of atmospheric water vapor were measured and fit to a previously developed diffusion‐based relaxation model. The retardance of a cross‐section of a silica glass rod heat‐treated at 650°C in lab air under applied torsional shear strain was also measured to confirm the presence of residual surface shear stress which was predicted by the decrease of torque with time for the rod. Together, these results confirm the low‐temperature fast surface stress relaxation which occurs when water vapor is present for both bending and shear stresses.

中文翻译：

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硅玻璃表面应力松弛的光弹性确认：纤维弯曲和杆扭转

对石英玻璃样品在低温下的应力下进行了各种热处理，随后使用偏光显微镜观察了它们在延迟方面的残余应力分布，证实了先前报道的快速表面应力松弛，同时提供了更详细的表征。测量了在存在大气水蒸气的情况下在恒定弯曲应变下热处理过的石英玻璃纤维的折射率分布，并将其拟合到先前开发的基于扩散的松弛模型中。还测量了在施加扭转剪切应变的条件下在实验室空气中于650°C热处理的石英玻璃棒横截面的延迟，以确认残余表面剪切应力的存在，该残余应力是由扭矩随时间的减小而预测的。杆。一起，