Abstract
The densities of melts in the systems Li2O-B2O3, Na2O-B2O3 and K2O-B2O3 were measured by a counterbalanced sphere method in the temperature range from 850°to 1250°C. The room temperature densities of alkali borate glasses, i.e., Li2O-B2O3, Na2O-B2O3, K2O-B2O3, Rb2O-B2O3, and Cs2O-B2 glasses were also determined. The results obtained show that the addition of alkali oxides to boric oxide causes the contraction of the B-O network. The results was interpreted in terms of the molar volume theory on the assumption that the atomic groups of borate form in the glasses.
