15N and 17O MAS NMR Studies of Yttrium Oxynitride Glasses

Abstract

High resolution Si-29, Al-27, N-15 and O-17 MAS NMR spectra have been collected for a series of yttrium oxynitride glasses with varying nitrogen contents. The results show that as the proportion of nitrogen in the glass increases, the proportion of [SiON3], [SiO2N2] and [SiO3N] coordinations systematically increase at the expense of [SiO4]. The Al-27 NMR spectra confirm the existence of [AlO4], [AlO5] and [AlO6] environments simultaneously in all samples, but it is difficult to unequivocally demonstrate the presence of Al-centred oxynitride environments ([AlO3N], [AlO2N2], etc) because of the breadth of the spectra. N-15 NMR spectra show that nitrogen occurs in two types of environment, either 2- or 3-coordinated by silicon, with the [NSi3] environment more dominant in oxynitride glasses with low nitrogen contents. O-17 spectra indicate three kinds of oxygen environment: bridging, nonbridging and ionic.