Structural studies of zinc polyphosphate glasses by nuclear magnetic resonance

Nuclear magnetic resonance (NMR) spectroscopy of solids and of liquids was used to study the structure of xZnO + (1 - x)P2O5 glasses prepared from a g lass melt in the composition range 0.35 less than or equal to x less than o r equal to 0.70. Relative concentrations of Q(n) units in the solid glasses have been compared with the liquid NMR spectra and with the predictions ba sed on the reorganization theory. Disproportionation reactions in glass liq uids of meta- and pyrophosphates are evident. Anisotropies of chemical shif t tensor for all phosphorus units are given. Structural changes associated with CSA parameters, including the presence of rings and chains are discuss ed. Both solid and liquid state NMR spectra show that ultraphosphate glasse s consist mainly of ring structures, while only chains are present in metap hosphates. (C) 2000 Elsevier Science B.V. All rights reserved.