Study on the thermochromic properties of Bi2O3-Li2O glasses

Reversible thermochromic properties were observed in Bi2O3-Li2O system glas ses. The temperature coefficient of optical absorption edge increases with increasing Bi2O3 content, implying that Bi2O3 is the main reason of thermoc hromism. The thermochromic mechanism is explained in terms of the temperatu re dependence of the optical energy gap E-g, caused mainly by the electron- phonon interaction. The low phonon energy and high electron density of Bi-O bond are important factors contributing to the electron-phonon interaction in these glasses.