Positron annihilation lifetime study of Ag-ion exchanged and heat treated soda lime glass

Slabs of soda lime silica glass (15% Na2O) were subjected to Ag+/Na+ ion exchange process and subsequent heat treatment. The change in glass structure and Ag states accompanied with these processes were studied using the positron annihilation lifetime spectroscopy. The positron annihilation lifetime measurements were performed with a fast–fast coincidence spectrometer employing a multi-parameter acquisition system. The lifetime parameters showed that the Ag+ ion reduction process takes place through two processes; the oxidation reduction reaction with Fe2+ impurities in the glass at heat treatment temperatures <500 °C, whereas at heat treatment ⩾500 °C the reduction takes place through the polymerization reaction. The results also indicated that the heat treatment at 600 °C enhanced the formation of Ag metal nanoparticle crystals through the structural relaxation revealed by the free volume defects.