Incorporation of nitrogen in Li2O-B2O3 glasses by conventional melting and via different sol-gel routes

Abstract

Nitrogen-containing Li2O—B2O3 glasses were prepared by six different melting and sol-gel processes. As pre-products conventional batches as well as dried gels were used, and the gels were prepared from aqueous or from alkoxide solutions. The nitrogen was brought into the glasses by adding BN, Li3N or NH3 at different stages of the procedure. The atmosphere during melting, the melting temperature and the melting time were also varied. The mtrogen-containing products were analyzed with respect to chemical composition and to glassiness. The amount of nitrogen dissolved was determined by means of the Kjeldahl method. The dependence of the nitrogen content obtained is discussed with respect to the methods apphed and the parameters varied. Compared to silicate and phosphate glass systems much less nitrogen could be introduced into the lithium borate glasses studied here. The maximum amount of nitrogen which is actually built into the borate glass network is 0.34 wt%.