XPS STUDIES ON OXYNITRIDE GLASSES IN THE SYSTEM SI-AL-O-N

X-ray photoelectron spectroscopic studies on Ca-Mg-Si-Al-O-N oxynitrid e glasses have been carried out. The nitrogen was incorporated into th e glass by means of substituting AIN by Al2O3 achieving nitrogen conte nts up to 10.0 at.%. Our results confirm the model that nitrogen tends to substitute non-bridging oxygen and at low concentration is solely bonded to silicon. The increase in the nitrogen content produces addit ional binding states for nitrogen, which are related to 'non-crosslink ed' nitrogen. Despite the presence of 11.6 at.% network modifiers (Ca, Mg) in the glass system studied, non-bridging oxygen could not be obs erved in the Ols signal. This was checked by preparing the samples in three different ways: fracturing in situ, fracturing under atmosphere and ion gun sputtering and also by comparison with results obtained fr om oxidic sodium silicate glasses. (C) 1997 Elsevier Science B.V.