Cross-sectional Raman micro-spectroscopy study of silver nanoparticles in soda–lime glasses

The growth and distribution of silver nanoparticles in ion exchanged glasses induced by thermal treatments in air at different temperatures were studied by means of cross-sectional Raman micro-spectroscopy analysis. Silver–sodium ion exchange of commercial soda–lime silicate glasses was done at 320 °C for 20 min, then the samples were treated by thermal annealing in air at temperatures in the range between 400 and 550 °C for 1 h. During the post-exchange thermal treatment, a further diffusion of silver from the surface toward the bulk occurred, together with the progressive formation of silver nanoparticles, whose fractional amount increased with an increase of the annealing temperature. Their average size and the related evolution as a function of the depth and of the treatment temperature were determined by Raman micro-spectroscopy analysis of the sample cross-section. Both aggregation of silver species and growth of silver nanoclusters are discussed on the basis of the theory of homogeneous nucleation in solids.