Résumé
Elastic (Rayleigh) and inelastic (Brillouin and Raman) scatterings are altogether measured in the same experimental conditions for germanium doped silica glass (5wt% GeO2). Taking into account that density and concentration fluctuations are frozen-in respectively at the fictive temperature Tf and at the chemical fictive temperature , a quantitative comparison of the different scattering processes demonstrates that the concentration fluctuations are the main reasons for the increase of the scattering. However the depolarized Rayleigh scattering is much stronger than in pure silica and also contributes to the increase of the total scattering whereas the increase of the Raman cross section due to the GeO2 introduction is much smaller.