Raman and infrared study of (PbO)x(P2O5)(1-x) glasses

The structure of binary (PbO)(x)(P2O5)((1-x)) glasses was investigated using Raman scattering and infrared spectroscopy, over the compositional range x = 0.5-0.68. The distribution of the phosphate groups (PO2)(-), (PO3)(2-), (P2O7)(4-) and (PO4)(3-), determined from the simulation of Raman spectra in the 800-1500 cm(-1) wavenumber range, indicates a significant disproportionation reaction :near the pyrophosphate composition and shows a phosphorus connectivity scheme in the glass structure in agreement with P-31 magic angle spinning NMR results. The low-wavenumber Raman spectra of glasses are discussed in the light of the spectra of crystals. The mode laying in the far-infrared region and due to lead-oxygen vibrations exhibits a composition-dependent wavenumber that correlates with bulk glass properties such as glass transition temperature. Copyright (C) 2002 John Wiley Sons, Ltd.