INFRARED AND CHEMICAL DURABILITY STUDIES OF SOME BINARY PBO AND ZNO PHOSPHATE-GLASSES AND THEIR CORRESPONDING SODIUM METAPHOSPHATE DERIVATIVES

Structural conclusions are obtained for glasses in the binary PbO and ZnO phosphate systems by IR spectroscopy. Alterations in bands, freque ncies and intensities as a function of chemical composition are interp reted and these indicate various types of interlink between Pb2+ and Z n2+ cations and the host network, especially, when they are incorporat ed as NWF's, Moreover, the metaphosphate structure, theoretically poss ible to be achieved in the structure of glasses with equimolar composi tions 50M(II)O . 50P(2)O(5) (mol%) (where M is Zn or Pb), is not confi rmed by their spectral patterns, However, this structure is confirmed to be achieved in the structure of glasses with 20Na(2)O . 30PbO . 50P (2)O(5) and 40Na(2)O . 10ZnO . 50P(2)O(5) (mol%). The dissolution rate s 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 ph osphate glasses (Van Water) and the previously suggested mechanisms fo r dissolution of phosphate glasses.