Comparative Study for Structure of Alkali Borate Glasses with and without Aluminum Oxide – Density Measurements

This paper reports on density measurements of alkali aluminoborate glass system (xR2O − yAl2O3 − (1 − x − y)B2O3, R = Li, Na where x = 20 or 30 mol% and y = 10 or 15 mol%), correlated with the glass structure. The samples have been prepared by using the melt-quenching technique. The density has been obtained by Archimedes principle using benzene as buoyant. The effect of nature of alkali and its composition with and without alumina is well studied. It is found that number of trigonal and tetrahedral boron units are related to the type of alkali oxide as well as the total concentration of alkali oxide in alkali borate glasses. The addition of aluminum oxide at the cost of borate induces the changes in the structure of glass network which further depends upon aluminum oxide and alkali oxide content. Keywords: Alkali borate, glasses, aluminum oxide, density, XRD