Raman spectra of TeO2-PbCl2 glasses

Samples of (TeO2)(1-y)(PbCl2-zOz12)(y) glasses (y=0.13-0.64; Z12 = 0.45-0.64) were prepared from TeO2 and PbCl2 starting compounds by melting in platinum crucibles. Results of chemical analysis proved that a chemical reaction between TeO2 and PbCl2 had proceeded in the course of the preparation process yielding tellurium chlorides and lead oxides. The glass samples were investigated using Raman spectroscopy. As follows from the qualitative analysis of Raman intensities the building of PbCl2-zOz12 into the glass network results in a breakdown of Te-O-ax(eq)-Te linkages, which means that the concentration of distorted TeO4 trigonal bipyramids (TBPs) decreases while the participation of trigonal pyramids (TPs) increases with increasing modifier content. The results indicate that lead oxides are probably built in the glass network as PbClmOn (m+a=6) octahedrons and OPb4 tetrahedra.