Compositional dependence of optical absorption spectra in mixed alkali borate glasses

The optical parameters of Fe3+- and Mn2+-doped Li2O–K2O–ZnO–B2O3 mixed alkali glasses have been determined through optical absorption studies. The glasses exhibit typical optical absorption spectra of Fe3+ and Mn2+ ions. Progressive substitution of Li with K induces non-linear variations in various optical parameters, such as optical band gap and Urbach energy with composition. Optical basicity, oxide ion polarizability, and interaction parameter values have been evaluated for all the glass specimens. The results show that these three parameters show a very small deviation from linearity with progressive substitution of Li with K ions.