Spectroscopic and structural studies on calcium borate glasses containing V2O5

This paper describes infrared, MAS-NMR and EPR studies on (40-x)CaO-60B(2)O(3)-XV2O5 (where x=1, 5,10,15 and 20 mol%) glass system. These studies indicate a strong composition dependence and the existence of characteristic borovanadate groups in these glasses. The scheme of modification of borate and vanadate groups has been explained by considering Sanderson's electronegativity principle. Analysis of infrared and MAS-NMR spectra suggests the presence of characteristic diborovanadate groups also in these glasses. The EPR spectra show a distinct hyperfine structure of V-51 The spectroscopic parameters vary systematically as a function of V2O5 concentration. The results are examined in view of the structural groups formed due to the presence of CaO as a modifier.