A Raman spectroscopic study on the microscopic origin of the photoinduced fluidity effect

Abstract

We report on a sub-band gap light scattering (Raman) investigation for a-As 2S 3 fibers subjected to external elongation stress in order to elucidate the photoinduced fluidity effect on a microscopic scale. Changes in the short-range order caused by the presence of the illuminating light have been detected. On the other hand, subtle modifications are revealed in the intermediate range order, manifested in the increase of the magnitude and in the modification of the frequency dependence for the depolarization ratio – in the low-frequency part of the spectrum – as a function of the applied stress. The “buckling model” proposed to account for the optical absorption tails in chalcogenide glasses seems quite relevant for explaining certain aspects of the experimental data.