Water-related IR absorption spectra for alkali zinc pyrophosphate glasses

The water-related first-order IR absorption spectra of zinc alkali pyrophosphate glasses in the 1400-4000 cm(-1) range are investigated. These spectra are shown to contain much greater number of spectral features than the spectra of silicate glasses. The quantitative treatment of spectra obtained is conducted with the dispersion analysis version using the convolution analytical model for the complex dielectric constant. The water-related species in glasses under study are shown to be both the bound hydroxyl group participating in the hydrogen bonding and the H2O molecule. The corresponding spectral bands are resolved and their frequencies are compared to those in the spectra of water-containing crystals. The stretching mode of bound hydroxyl is shown to be split 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 the bound hydroxyl groups in the glass samples. The stretching modes of the H2O molecule are shown to result in several bands in the 2800-3500 cm(-1) range. (C) 1998 Elsevier Science B.V. All rights reserved.