Reversible redox and clusterization of silver in glasses by X-ray irradiation and heat treatment: Mechanism of photochromic behavior of halogen-free silver-doped glass

We investigated photochromic behavior, i.e. X-ray irradiation and post-heat-treatment-induced reversible redox and clusterization reactions of silver, in soda-lime silicate (74SiO2·16Na2O·8CaO·2Al2O3) and aluminosilicate ((75 − x)SiO2·25Na2O·xAl2O3 (x = 5–25)) glasses. Generation and annihilation of silver nanoparticles were observed for soda-lime silicate and x = 5 aluminosilicate glasses doped with 0.05 wt.% or less of Ag while no nanoparticles were formed for x = 15–25 aluminosilicate glasses even doped with 0.5 wt.% of Ag. These results were analyzed from the viewpoints of the reaction kinetics and network structures of the glasses.