Properties of selected zirconia containing silicate glasses III

Viscosity, density, glass transition temperature Tg+ refractive index, n(D), molar refractivity, Rm, and chemical durability, CD, of xNa(2)O center dot(15x)K2O center dot yCaO center dot(10-y)ZnO center dot zZrO(2)center dot(75-z)SiO2 (x=0, 7.5, 15; y=0.5, 10; z= 1, 3) glasses were measured. The temperature dependence of viscosity was described by Andrade's equation and the temperature independent values of the viscous flow activation energy, E-n, were calculated. The effect of K2O/Na2O, ZnO/CaO, and ZrO2/SiO2 substitution on the values of V-m, n(D), R-m, T-g, E-n and CD was quantified by multilinear regression analysis. It was statistically confirmed that the K2O/Na2O substitution increases the value of V-m, R-m, T-g, E-n, and CD and decreases the value of n(D). The ZnO/CaO substitution increases the value of T-g and decreases the value of V-m, n(D), R-m, E-n and CD. The ZrO2/SiO2 substitution increases the value of n(D), R-m, T-g and E-n and decreases the value of V-m, and CD.