Soda lime glass substrate

1. Adsorbed Water Can Make Glass Weaker or StrongerSeong H. Kim, Pennsylvania State University, DMR 1207328 • Outcome:Researchers at Penn State elucidate the structure of water at glass surfaces in humid ambience. • Impact: Although multicomponent silicate glasses are involved in a variety of advanced technical applications, little is known about its surface chemistry in humid ambience. Understanding the effects of water adsorbed on glass will aid control of surface reactions and properties of multicomponent glass materials. • Explanation: The spectra shown here indicate the presence of three distinct water species or structures on soda lime glass. Their populations vary with the relative humidity (RH) of the ambience. When a soda lime glass is scratched with a pyrex ball in low humidity, the soda lime glass gets worn. In high humidity, however, the pyrex ball wears and its debris are deposited on the soda lime glass. This wear behavior transition upon increase of humidity can be correlated with the growth of the water peak at 3200cm-1 on the soda lime glass, which is putatively attributed to the hydronium (H3O+) ion. When Na+ ions are exchanged with larger ions (such as K+ in the Gorilla glass used for iPhone), then a compressive stress can be generated in the silicate network and the glass surface becomes tougher. The similar effect is expected when the H3O+ ions (larger than Na+) are incorporated in the soda lime glass surface at high humidity. Pyrex ball counter-surface RH 90% RH 20% Soda lime glass substrate