Glass-forming ability, structure and physical properties of ZnO-WO3-P2O5 glasses
Ladislav Koudelka, Jiri Subcik, Petr Mosner, Ivan Gregora, Lionel Montagne, Laurent Delevoye
Glasses in the ternary system ZnO–WO3–P2O5 were studied. The glass-forming region of ZnO–WO3-P2O5 system has been determined and basic physical properties of the prepared glasses were obtained. Structure and properties of the glasses were studied in three compositional series (100-x)[0.5ZnO-0.5P2O5]-xWO3 and (50-y)ZnO-yWO3-50P2O5 and zZnO-20WO3-(80-z)P2O5 by Raman and 31P NMR spectroscopies. In the compositional series (100-x)[0.5ZnO-0.5P2O5]-xWO3 homogeneous glasses were prepared in the concentration region of 0-60 mol% WO3. Their glass transition temperature (Tg) increases with increasing WO3 content within the range of 460-622°C. 31P MAS NMR spectra of the glasses show on a steady depolymerization of phosphate chains by the incorporation of tungstate structural units. Raman spectra reveal the existence of isolated WO6 units in the glasses with a low WO3 content and increasing clustering of WO6 units by the formation W-O-W bonds in glasses with a high WO3 content.
