Effect of Li_2O on Viscosity and Thermal Expansion of Silicate Glass

摘要

Viscosity, coefficient of thermal expansion, glass transition temperature and dilatometric softening temperature of soda-lime-silicate glass doped with Li_2O were investigated by the rotating crucible viscometer and dilatometry, the melting temperature and activation energy for viscous flow of the studied melt were derived on the basis of Arrhenius Equation, in order to reveal the effects of Li_2O on the properties of soda-lime-silicate glass. The results showed that the viscosity of soda-lime-silicate glass was effectively decreased and the melting temperature decreased from 1457°C to 1420°C with the increase of Li_2O from 0 to 1.0wt%, furthermore, the T_g and T_s reduced 30-40 °C. The AT responded to the range of viscosity of glass formation (η=10~3-10~7Pa.s) increased from 309.84°C to 313.45°C, and the activation energy for viscous flow decreased form 178.47 kJ.mol~(-1) to 168.34 kJ.mol~(-1). The CTE a (25～40°C) of specimen doped with 0.4% Li_2O was 92.048 x 10~(-6)C~(-1) and the lowest of the samples.