LOW-FREQUENCY RAMAN-SPECTRA AND STRUCTURAL CORRELATIONS IN METAL-OXIDE GLASSES

Raman and FT-IR studies are reported for the (1 - x)TeO2-xMgO system w here 0.05 < x < 0.40. The destruction of the three-dimensional TeO4 ch ain network with increase in MgO concentration is followed by comparin g the intensities of the TeO3 and TeO4 stretching-mode bands in the 70 0 cm(-1) spectral region. Examination of the same systems after recrys tallization yields spectra in which the basic contour often resembles the band envelope of the initial glasses. The decomposition of the Bos on peak and its shoulder leads to the suggestion that the strongest fe ature in the band mass can always be assigned to the long-range descri ptive element but the broad shoulder seems to be related to modes asso ciated with more medium-range external interactions within the polyhed ron latticework. (C) 1997 Elsevier Science B.V.