Low concentration of Si nanoparticles (n-Si) produced by a ball milling method were introduced into a SiO2 matrix by the sol-gel method. These SiO2 sol-gel suspensions were prepared with high water-TEOS ratios. The samples obtained have high silanol concentration as was proved by infrared spectroscopy. The silanol structures of this samples are resistant for temperature as high as 800°C. Raman scattering measurements showed evidence of a photo-oxidation effect of the nSi particles embedded into the SiO2 matrix with high silanol concentration. The nanometric size of the Si particles was computed from Raman scattering measurements. The photo-oxidation effect was observed as a gradual shifting and broadening of the Raman signal due to the reduction of the particle size from 14 to 7 nm.