Laser-induced glass-crystallization phenomena ofGeSe2investigated by light scattering

Recrystallization of glassy ${\mathrm{GeSe}}_2$ under laser irradiation has been studied with use of Raman spectroscopy. A threshold irradiation power level below which no changes in the local molecular structure of the system can be detected has been defined. For an irradiation power above the threshold, three stages of transformation have been identified: The first stage is characterized by the nucleation of clusters or submicrocrystallites which remain embedded in a continuum glass matrix. The second stage is characterized by the coexistence of clusters of various sizes. Up to this stage, the system is fully reversible. The last stage is reached when the crystallites coalesce to form a polycrystalline material.