Mixed valence effect of Se6+ and Zr4+ on structural, thermal, physical, and optical properties of B2O3–Bi2O3–SeO2–ZrO2 glasses

Abstract

Conventional melt quench technique has been used to synthesize the highly polarizable glass system with composition (70B2O3–30Bi2O3), (70B2O3–25Bi2O3–5SeO2) and (70B2O3–23Bi2O3–5SeO2–2ZrO2)in (wt%)abbreviated as BB, BBS and BBSZ respectively. Structural, thermal, physical and optical properties of the modified glass system have been studiedusing XRD, DSC, FTIR, Raman and UV–Vis Spectroscopy. XRD have been performed to confirm the amorphous nature of samples. The calculated OPD values and DSC analysis confirmed decrease in Tg on the addition of SeO2 and ZrO2 content. FTIR and Raman data revealed the existence of characteristic bands of [BiO3], [BiO6], [BO3], [BO4], [SeO42−], [SeO32−] units and Zr–O–Zr linkages. The effect of ZrO2 on the structural stability has been observed using density and molar volume. Adecrease in band gap resulting from the increase in NBO's has been confirmed by UV–Vis spectroscopy as well as from physical parameters like metallization criterion and urbach energy. An increase in refractive index is observed on the addition of SeO2. The parameters electronic polarizability, optical basicity and electronegativity confirms the ionic character of the studied glass samples.