Fe-substituted Co-Li bismuth borate glasses

Abstract

Cobalt lithium bismuth borate glasses substituted with different amounts of iron in the compositional range of xFe2O3·(20 − x)CoO·30Li2O·10Bi2O3·40B2O3 (x = 0, 5, 10, 15 and 20 mol%) have been synthesized via melt quench route. The synthesized glasses are investigated for their crystallization kinetics behavior through non-isothermal differential scanning calorimetry (DSC) measurements and their optical absorption behavior through UV–Vis spectroscopic measurements. Thermal activation energies corresponding to the crystallization and glass transition properties are evaluated and reported. The variation in the characteristic temperatures (glass transition temperature, crystallization temperature and melting temperature) with change in heating rate and change in the composition of iron oxide is discussed. The optical absorption results are analyzed to evaluate the optical band gaps corresponding to indirect allowed and forbidden Mott transition. The band tailing parameter (B) corresponding to each Mott transition has also been evaluated and reported. The Urbach’s (ΔE) energy is calculated by analyzing the fundamental absorption edge, and the obtained results are reported.