Light Scattering Studies on the Glass Transition and the Structure in Silica Glass

Peculiar properties in silica glass were investigated by the light scattering measurements. It was shown that the glass transition temperature can well be determined by measuring temperature dependence of the light scattering intensity. Relations between the glass transition temperature, the fictive temperature, cooling rate, and viscosity were clarified in low and high OH-containing silica glasses, and the effect of OH ions on the slow dynamics was revealed. On the processes of supercooled liquid\leftrightarrowsliquid, the light scattering intensity was found to change drastically at a melting temperature of cristobalite. This result strongly suggests that medium-range order structures, microcrystallites, exist in silica glass.