Structure and ac conductivity of sodium–lead–cadmium metaphosphate glasses
Résumé
Sodium–lead–cadmium phosphate glasses having a mol% composition (40−y)Na2O–yCdO–10PbO–50P2O5 (0≤y≤40) were prepared by using the melt–quench technique. They have been characterised by infrared spectroscopy, Raman spectroscopy and 31P magic angle spinning nuclear magnetic resonance (MAS-NMR). Infrared and Raman spectroscopies reveal the formation of P–O–Pb and P–O–Cd bonds, which replace P–O–+Na bonds. MAS-NMR spectroscopy shows that no metaphosphate network depolymerisation occurs when y increases. Thus, both PbO and CdO act as the network modifiers. Systematic variations of the glass transition temperature, density, and molar volume observed are in agreement with these results. Ionic conductivity is correlated to the structural model.