Internal Friction of Proton‐Exchanged Li2O·Al2O3·2SiO2 Glass

Abstract
Protons were introduced into the surface of an Li2O·Al2O3·2SiO2 glass fiber (0.5 mm in diameter) by ion exchange in NH4HSO4 at 366°C for 21 h. Infrared absorption measurements established that the protons were associated with bridging oxygen ions. After ion exchange, the magnitude of the alkali internal friction peak decreased and a new peak appeared at ∼220°C. This new peak is attributed to the interaction of alkali and hydrogen ions, independent of the presence of nonbridging oxygen ions.