THE DENSITY OF SODIUM BOROSILICATE GLASSES RELATED TO ATOMIC ARRANGEMENTS

Densities in the glass, RNa2O·B2O3·KSiO2, have been measured over wide ranges of composition. The measurements were made for fixed K while varying R. The results were analyzed in terms of a model for the atomic arrangements proposed by Dell, Bray, and Xiao and a model for the density modified from previous studies on the alkali borates. The analysis yielded relative associated volumes of the borate structural units as well as two volumes which characterize the silica network. These volumes were then compared with those determined from ionic radii. Predictions were also made for the densities of glasses in the sodium silicate system. © 1990.