Abstract
It has previously been shown that the fading rate of photoehromic glasses depends on darkening conditions. A trapped-hole diffusion model was proposed to explain this effect (Araujo 1968, 1971).
In this paper a temperature-dependent recombination term which decreases exponentially with electron-hole separation is included in the diffusion model. Peculiar low-temperature effects are predicted and these are observed in some photochromic glasses.