Thermal poling of soda-lime glass which was doped with spherical or ellipsoidal silver nanoparticles has revealed what we believe to be a phenomenon of general interest in the physics of nanocomposite materials: The field-assisted dissolution of metal nanoparticles embedded in glass. Macroscopically, this phenomenon manifested itself as poling-assisted bleaching of the glass in the sense that the glass became more (or even completely) transparent under the anode. The phenomenon is physically interpreted in terms of the ionization of metal nanoclusters followed by the removal of ions from the clusters and their drift in the depth, under the action of the extremely high electric field which is created underneath the anodic surface during poling. The underlying physical mechanism is expected to offer unique opportunities for the control of structural and optical properties of nanocomposite glasses. (C) 2004 American Institute of Physics.