MULTISITE EFFECT IN THE IR-SPECTRA OF VARIOUS INORGANIC GLASSES - EXPERIMENTAL-EVIDENCE AND STRUCTURAL REASONS

Data on the IR spectra of various glasses are reviewed and the spectra of glasses such as vitreous barium metaphosphate, alkali zinc pyropho sphate glasses, and binary borate glasses are subjected to an addition al quantitative treatment. A multi-band pattern in the range of the as ymmetric stretching modes is shown to occur in the spectra of these gl asses. The main reason for the splitting of the asymmetric stretching modes of basic structural groups is shown to be a multi-site effect du e to the occurrence of two or more translationally non-equivalent posi tions of structural groups in the regions of phonon localization. Inve stigation of the relative intensities of the spectral components origi nated from the same stretching mode as a function of glass composition is suggested as a possible tool for the study of subtle features of g lass structures. (C) 1998 Elsevier Science B.V. All rights reserved.