Stresses in ion-exchange layers of soda-lime-silicate glass

This paper presents a new method to determine both the magnitude and the sign of the surface stresses that develop as a consequence of sodium/hydrogen ion exchange in soda-lime-silicate glass immersed in water. At 90 degrees C, very thin layers that develop at the surfaces of polished glass specimens are found to have extremely high compressive stresses, -2.4 GPa. The negative sign of the stress is consistent with earlier findings that the ion-exchange process involves hydronium ions (H3O+) and not bare protons (H+).