Characterization and structural studies of vanadium doped lithium-barium-phosphate glasses

摘要

Characterization and structural studies of (P _2O _5) _(49.5)(V _2O _5) _(0.5)(BaO) _x(Li _2O) _(50-x) (where x = 0, 5, 10, 15, 20, 25 mol%) glasses are reported. These glasses were prepared using the conventional melt quenching technique. X-ray diffraction and differential scanning calorimetry measurements were performed to confirm their amorphous nature. Infrared spectra of these glasses show absorption peaks in the ranges 1273-1267; 1098-1088; 1008-1018; 899-889; and 795-760 and 506-474 cm ~(-1) corresponding to P=O, P-O -, (P-O-P) _S, (P-O-P) _(AS), and O-P-O group vibrations, respectively. Thermal stability factor (s) has been evaluated using the values of T _g and T _c. These glasses exhibit high transition temperature (T _g) and high thermal stability factor (s) indicating that they are thermally stable. Refractive index of the glasses lies in the range 1.59-1.49. Electron paramagnetic resonance spectroscopy of V ~(4+) show characteristic hyperfine split signal arising from the vanadyl group in this glass matrix. The results are discussed by considering the structural modification of the phosphate network.