Chalcogenide glasses are amorphous semiconductors with a number of interesting properties required for photonic
devices. Particularly, their optical properties can be tuned through the change of the glass composition. We investigate
second-order nonlinear optical properties of chalcogenide glass (Ge27Se64Sb9) thin films fabricated by thermal
evaporation. The strong second-harmonic generation observed for the samples investigated is analyzed as a function of
incident polarization. Furthermore, the role of multipole effects in second-harmonic generation is also studied by using
two beams at the fundamental frequency. Our results suggest that the higher-multipole effects are present and contribute
significantly to the second-harmonic response of chalcogenide the samples.