The correlation between the structural, optical, and electrical properties in mixed alkali fluoroborate glasses containing vanadium ions

Lithium sodium fluoroborate glasses doped with vanadium ions were prepared by melt annealing technique. The structural investigation shows the formation of probable BO3, BO4, BO2F, and BO3F structural units. Moreover, vanadium ions are mostly presented in such glasses as V4 + state and it may form non-bridging oxygens (NBOs). The decreasing in the optical band gap values as a function in the glass composition or vanadium content approves the formation of NBOs. The refractive index is estimated directly from the optical band gap values by using the Dimitrov-Sakka relation. Density, molar volume, molar refraction, and metallization criterion were studied and explained in terms of the structural changes obtained by the impact of the vanadium ions. Thermal activation energy is explained by the formation of Non-bridging oxygens and the effect of V2O5 dopant.