Optical absorption spectrum of (LiCl)x(P2O5)1−x glass

A series of glasses (LiCl)x(P2O5)1−x with x=0.1–0.6 in the interval of 0.05 were prepared by a single-step melting process with LiCl and P2O5 as starting materials. Their density and absorption spectra in the ultra-violet visible (UV-Vis) region have been recorded at room temperature. The Urbach rule has been applied to evaluate the fundamental absorption edges for all the glasses from the obtained spectrum. The optical band gaps were calculated from the absorption edge and it was found that the optical band gap, Eopt, depended on the glass composition. The optical band gap decreases to lower energies and shifts to longer wavelength with the increase in LiCl content in glass. The absorption edge is attributed to indirect transitions. The densities of glasses were found to be varying between 2.33 and 2.52 g cm−3 for mole fraction of 0.1–0.6. The average density was 2.42 g cm−3 and no evidence of anomalous densities’ behaviour was observed.