Abstract
Seven soda boric oxide glasses and one each of potash boric oxide and Iithia boric oxide glasses were melted with chromic oxide and sodium Chromate using air as furnace atmosphere till redox equilibrium between trivalent and hexavalent chromium was attained. Estimation of different oxidation states was done by chemical analysis. The present study indicates that both alkali content and total chromium content influence redox equilibrium. The results suggest that non-bridging oxygen ions appear in soda-boric oxide glass in the range of 20 to 23% Na2O content.