THE SHORT-RANGE STRUCTURE OF ZINC POLYPHOSPHATE GLASS

P-31 magic angle spinning nuclear magnetic resonance (MAS-NMR) spectro scopy and Raman spectroscopy have been used to examine the polyhedral arrangements in xZnO . (1 - x)P2O5 (0.50 less than or equal to x less than or equal to 0.71) glasses. The depolymerization of P metaphosphat e chains by the addition of ZnO is quantitatively described by the inc rease in the concentration of Q(1)-phosphate sites, determined from th e P-31 MAS-NMR spectra. When x > 0.60, the NMR and Raman spectra exhib it peaks due to Q(0) and Q(2) tetrahedra, indicating that structures d isproportionate in glass melts near the pyrophosphate composition. The splitting of the Raman peak due to the Q(1) terminal oxygen stretchin g mode indicates that a variety of P-O-Zn bonds participate in the pol yphosphate glass structure. The complex mixture of P and Zn polyhedra contributes to the glass-forming tendency of the high ZnO (> 60 mol%) compositions.