Abstract
Reorientation cycles of photo-induced anisotropy in an amorphous chalcogenide film have been investigated. The kinetics of the reorientation process show a simple power-law time dependence on short time scale. A model based on bistable defect centres with widely distributed relaxation times is proposed. It is speculated that excitations from or to the band tails might be involved in the reorientation process. Finally the influence of circularly polarized light on the induced anisotropy is discussed. An interesting ‘back-shoot’ effect is shown which gives further support to the proposed wide distribution of relaxation times.