Clustering of silver atoms in hydrogenated silver-sodium exchanged glasses

The diffusional growth regime of silver clusters in hydrogenated silver-sod ium exchanged glasses has been numerically analysed. The diffusion coeffici ents of the three elements that contribute to silver cluster formation, nam ely H, Ag+, and Ag-0, have been established. The activation energy of the r eactant Ag-0 diffusion coefficient is consistent in the three analysed diff erent experimental results: Ag loss through evaporation, near-surface Ag ac cumulation, and optical absorption density. The calculated Ag-0 diffusion c oefficient accounts for the threshold time necessary to obtain a cluster si ze to give rise to a detectable absorption.