Formation of nanoclusters in silver-doped glasses in wet atmosphere

Thermal stability of silver ions in silicate glasses in dry and wet (0.5 - 50% of water content) atmosphere under elevated (160-230 °C) temperature is studied. The glass is doped with silver using silver-to-sodium ion exchange procedure conventionally used for the formation of optical waveguides. It is found that the isothermal annealing of glasses doped with Ag⁺ ions in a wet argon atmosphere leads to the reduction of silver to metallic state and to the formation of silver nanoclusters in the glass body. The clustering in the course of water diffusion into the glass was studied by optical spectrometry. The clusters were not formed during annealing in a dry atmosphere at the same temperatures.