MATHEMATICAL-MODEL FOR ION REFRACTIVITY OF OXYGEN IN SLAGS

A mathematical model to estimate the ion refractivity of oxygen in the binary and ternary silicate systems has been developed based upon a s imple structural model for silicate glasses. The ion refractivity R-o of oxygen in binary silicate glasses can be described by the equation R-o = R-o(o) + Delta R-o[2x/(2-x)], where R-o(o) and Delta R-o are the ion refractivity of oxygen for SiO2 glass and the increase in the ion refractivity of oxygen due to the presence of non-bridging oxygen ion s, respectively, and x is the mole fraction of alkali or alkaline eart h metal oxide. Published data for the ion refractivity of oxygen for a lkali and alkaline earth silicate glasses have supported that this mod el is reasonable, and values of Delta R-o, have been determined as 0.6 9 for Li2O, 1.19 for Na2O, 1.56 for K2O, 1.10 for CaO and SrO, and 1.3 0 for BaO. The value of QR, means the effective basicity for these oxi des doped into SiO2 glass. Furthermore, the model has been extended to the ternary silicate system.