The induced optical absorption spectra of 70GeO 2 · 10Ga 2 O 3 · 20Li 2 O glasses are measured. A process is described for producing photosensitive layers on alkali germanate glasses using ion-exchange diffusion from salt melts containing silver nitrate. The effects of the sensitizer (Ce 3+ , Fe 3+ , and Fe 2+ ) and preparation, UV irradiation, and heat treatment conditions on the mechanisms of silver reduction in the surface layer of germanate glasses are examined. The results demonstrate that colloidal silver particles can be produced via ion exchange at 350 ° C in glasses containing 0.1 wt % Fe 2 O 3 . The particle diameter in a glass prepared under reducing conditions is estimated at 2.5 nm.