RAMAN AND BRILLOUIN-SCATTERING AND XPS SPECTROSCOPY IN NAPB0.5BI0.33PO4 GLASS EVOLUTION AS A FUNCTION OF TEMPERATURE

Raman spectra of glassy, recrystallised and liquid NaPb0.5Bi0.33PO4 ha ve been obtained in situ to a temperature of 1170 K. We analyze the mo dification of the spectra vs, temperature in terms of frequencies assi gned to the cation vibrations and of frequencies assigned to PO43- gro up vibrations, particularly the range 900-1200 cm(-1) which was deconv oluted. Brillouin scattering experiments have been carried out between 298 K and the recrystallisation temperature. The temperature evolutio ns of the Brillouin frequencies and of the lowest Raman frequency exhi bit the same dependence. Spectra obtained from X-ray Photoelectron Spe ctroscopy (XPS) revealed the existence of two lead and bismuth cations . (C) 1998 Elsevier Science B.V. All rights reserved.