Infrared spectroscopy of wide composition range xNa sub 2 S+(1-x)B sub 2 S sub 3 glasses

Glasses are prepared with 0 < or =x < or =0.33 in a low-alkali region and 0.55 < or =x < or =0.8 in a high-alkali region. Structures of glasses in the former are dominated by creation of tetrahedral B units similar to those in alkali borate glasses. For pure B sub 2 S sub 3 , large fraction of six-membered rings is found. As alkali is added, the vibrational frequency of the six-membered ring mode decreases, but not the intensity, and a new band grows. Authors propose that the fraction of tetrahedral borons increases with alkali sulfide content. Observations suggest that isolated six-membered rings persist even in the presence of tetrahedral borons. For the high-alkali glasses, both the six-membered rings and tetrahedral B structures are destroyed with formation of isolated orthothioborate groups, Na sub 3 BS sub 3 . The ir spectra of high-alkali glasses show a monotonic increase in symmetry and simplicity. 60 refs.