Infrared and chemical durability studies of some binary PbO and ZnO phosphate glasses and their corresponding sodium metaphosphate derivatives

Abstract

Structural conclusions are obtained for glasses in the binary PbO and ZnO phosphate systems by IR spectroscopy. Alterations in bands, frequencies and intensities as a function of chemical composition are interpreted and these indicate various types of interlink between Pb2+ and Zn2+ cations and the host network, especially, when they are incorporated as NWF's. Moreover, the metaphosphate structure, theoretically possible to be achieved in the structure of glasses with equimolar compositions 50M(II)O·50P2O5 (mol%) (where M is Zn or Pb), is not confirmed by their spectral patterns. However, this structure is confirmed to be achieved in the structure of glasses with 20Na2O·30PbO·50P2O5 and 40Na2O·10ZnO·50P2O5 (mol%). The dissolution rates of most of the studied glasses were measured as a function of pH and variation in chemical composition. The results are discussed in light of the conclusions obtained from the IR study, structural model of phosphate glasses (Van Wazer) and the previously suggested mechanisms for dissolution of phosphate glasses.