The structure of Ag2O-MxOy-TeO2 (MxOy = WO3, MoO3, P2O5, and B2O3) glasses
was investigated by Raman spectroscopy. Raman spectra shows that in additio
n to the expected TeO4 trigonal bipyramid (tbp), the TeO3 trigonal pyramid
(tp), and the WO4/WO6, MoO4/MoO6, PO4, and BO3/BO4 polyhedra are present in
tungstotellurite, molybdotellurite, phosphotellurite, and borotellurite gl
asses, respectively. The relation between the MxOy content and the intensit
y ratios of the deconvoluted Raman peaks I-720/I-660 and I-780/I-660 were s
tudied. From the temperature variation study of the Raman spectra, it was o
bserved that there is an increase in the TeO3 units with the increasing tem
perature. Although crystallization occurred easily during heating of the gl
asses in any system, the melts hardly ever crystallized during cooling. (C)
1999 Elsevier Science Ltd.