STRUCTURE OF BOROVANADATE GLASSES STUDIED BY RAMAN-SPECTROSCOPY

Borovanadate glasses(1 - x)[B2O3-yLi(2)O]-xV(2)O(5) with 0 less than o r equal to x less than or equal to 1 and 0 less than or equal to y les s than or equal to 1 have been prepared and systematically studied by Raman spectroscopy, The results have been compared with glass transiti on temperature measurements. The Raman spectra exhibit a characteristi c band at about 900 cm(-1) whose shape and frequency an dependent on b oth V2O5 and Li2O concentration, The study of the line shape has shown that vanadium-oxygen structural units formed in the glasses are VO4 t etrahedra and VO5 pyramids according to the Li2O content. It is also o bserved that V2O5 behaves as modifier or as glass former in regard to the boron-oxygen network.