Ceramics-Silikáty 52, (2) 102 - 108 (2008)

Viscosity, density, glass transition temperature, T_g, refractive index, n_D, molar refractivity, R_m, and chemical durability, CD, of xNa₂O·(15-x)K₂O·yCaO·(10-y)ZnO·zZrO₂·(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_η, 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_η, 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_η, 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_η, and CD. The ZrO₂/SiO₂ substitution increases the value of n_D, R_m, T_g, and E_η, and decreases the value of V_m, and CD.