Raman scattering on a series of glass composite samples containing CdTe1-xSex and CdS1-xSex nanocrystals with radii in the range [2nm, 12.5nm] is reported. By properly considering the size dependence of strain and confinement effects, the chemical composition and the lattice contraction is assessed. The polarization analysis of the scattering indicates that the Fröhlich electron-phonon interaction increases at decreasing the nanocrystal size. © 1994 Academic Press. All rights reserved.