WATER-RELATED IR-ABSORPTION-SPECTRA FOR ALKALI ZINC PYROPHOSPHATE GLASSES

The water-related first-order IR absorption spectra of zinc alkali pyr ophosphate glasses in the 1400-4000 cm(-1) range are investigated. The se spectra are shown to contain much greater number of spectral featur es than the spectra of silicate glasses. The quantitative treatment of spectra obtained is conducted with the dispersion analysis version us ing the convolution analytical model for the complex dielectric consta nt. The water-related species in glasses under study are shown to be b oth the bound hydroxyl group participating in the hydrogen bonding and the H2O molecule. The corresponding spectral bands are resolved and t heir frequencies are compared to those in the spectra of water-contain ing crystals. The stretching mode of bound hydroxyl is shown to be spl it into a series of components in the 1600-3000 cm(-1) range, which is interpreted in terms of the multi-site effect. The occurrence of the multi-site effect for the impurity-related mode is assumed to indicate the phonon-like nature of this mode and non-uniform distribution of t he bound hydroxyl groups in the glass samples. The stretching modes of the H2O molecule are shown to result in several bands in the 2800-350 0 cm(-1) range. (C) 1998 Elsevier Science B.V. All rights reserved.