Name�FTakahiro Suwa

Title�FViscous flow mechanism based on free volume theory of soda lime silicate glasses over wide temperature range

Professor�FKazumasa Matusita

summary�FIn recent years, high qualities of new glasses used as optical material and precision instrument have been demanded and viscosity is one of the most important physical properties relating the manufacturing process.
In this study, density and viscosity of soda lime silicate glasses were measured from below Tg to melting temperature. These experimental result were analyzed based on free volume theory. As a result, it was found that the activation energy for viscous flow tends to increase as the thermal linear expansion coefficient increases.
It is concluded that while Fulcher equation can be applied only above Tg, the equation based on free volume theory agrees with experimental values over wide temperature range from melting temperature to below Tg.