The glasses with composition 64TeO2–15ZnO–(20x)CdO–xBaO–1V2O5 (0 6 x 6 20 mol%) were prepared
by conventional melt quenching technique. X-ray diffraction analysis was used to confirm the amorphous
nature of the glasses. The optical absorption studies revealed that the cut-off wavelength (ka) decreases
while optical band gap energy (Eopt) and Urbach energy (DE) values increase with an increase of BaO content.
Refractive index (n) evaluated from Eopt was found to decrease with an increase of BaO content. The
physical parameters such as density (q), molar volume (Vm), oxygen packing density (OPD), optical basicity
(K), molar refraction (Rm), and metallization criterion (M) evaluated and discussed. FTIR and Raman
spectroscopic studies showed that the glass network consists of TeO4, TeO3+1/TeO3 and ZnO4 units as
basic structural units. The glass transition temperature (Tg) of glass sample, onset crystallization temperature
(To) and thermal stability DT were determined from Differential Scanning Calorimetry (DSC).
Using electron paramagnetic resonance (EPR) spectra of vanadium glasses the spin Hamiltonian parameters
and dipolar hyperfine coupling parameters of VO2+ ions were calculated. It was found that V4+ ions in
these glasses exist as VO2+ in octahedral coordination with a tetragonal distortion and have C4V symmetry
with ground state dxy. Tetragonality (Dgk=Dg?) of vanadium ion sites exhibited non-linear variation with
BaO content.
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