The kinetics of the photochromic effect in Bi12SiO20:Mn

The time dependences of light-induced absorption in Bi12 SiO20 doped with Mn for different illumination intensities 0.1–12 mW cm−2 at temperatures of 300–500 K were measured. The kinetics of the photochromic effect in sillenites were investigated. The dependences of the kinetics on the temperature and on the light intensity in the colouring and thermal bleaching processes were obtained. On the basis of these results a model of the sillenites' photochromism has been proposed. The photochromism of the sillenites was interpreted as the charge transfer process of the impurity centres with the synchronous creation or vanishing of the small bound polaron.