A combination of direct current (d. c.) electric field and moderately elevated temperature is applied to a glass with embedded spherical silver nanoparticles in the near surface region. The field-assisted dissolution of silver nanoparticles leads to the formation of a layer of percolated silver clusters with modified optical properties beneath the glass surface. The distance between this produced buried layer and the surface of the sample can be controlled by the magnitude of the applied voltage. The same holds for the interferential colors observable in reflection. The presented technique is easy to implement and paves a route towards the engineering of the optical properties of metal-doped nanocomposite glasses via modification of the spatial distribution of metallic inclusions. (C) 2005 Optical Society of America.