This work is an attempt to apply conventional mechanical testing to to characterise the photoinduced viscoelastic behaviour of chalcogenide glasses. Creep or relaxation-recovery experiments are usually performed to characterise the delayed elastic contribution to deformation, during thermally activated flow. In this article, relaxation-recovery is used to characterise delayed elasticity under irradiation condition and to investigate the influence of the photon irradiation on the viscoelastic behaviour. It is showed that thermally activated processes and photoinduced ones are decoupled. The viscoplastic deformation under irradiation is the sum of thermally activated and photoinduced processes. As soon as the irradiation ceases, chalcogenide glasses behave exactly as if they had never been irradiated. The photoinduced viscoelastic behaviour seems to be solely due to transient photoinduced structural defects.
