Shuko ENDO

Viscous flow mechanism of phosphate glasses based on free volume theory

Kazumasa MATUSITA

High quality and homogeneity are essential properties for new glass.The properties of melt are very important in manufacturing process.In present study, the author measured density and viscosity of melt of metaphosphate glasses (K2O-PbO-P2O5 ternary system), the relationship between volume and viscosity was analyzed based on free volume theory.
Density and viscosity that are measured by using Archimedes two-sphere method and Pt sphere moving method.It was found that the obtained density and viscosity were increased with the PbO content.
Constants in Doolittle equation were calculated by optimization and it is found that B and V0 interrelate with bonding strength and ionic radius respectively.It was also found that viscosity can be represented by free volume theory in wide temperature range including below glass transition temperature and it was concluded that viscosity is determined by volume.