FORMATION AND STRUCTURE OF GLASSES CONTAINING SEO2

The glass formation regions for the SeO2-MoO3-MnOm systems (MnOm = Bi2 O3, Sb2O3, CuO, MgO) have been determined for a slow cooling rate from the melts under excess oxygen pressure. The stable glasses are situat ed near the SeO2 corner of the phase diagram. It has been established by IR spectroscopy that the main structural units, which form the netw ork of SeO2-MoO3 glasses, are SeO3, SeO3 (Se = O), MoO6 and Mo2O5 grou ps. Several topological models are proposed for the structure, dependi ng on the composition. On the basis of the structural peculiarities, c onclusions are drawn about the glass-forming tendency in selenite syst ems.