The alteration of natural silicate glasses is driven by processes near the earth surface, which affected the glasses over geological time periods. Alteration of glass comprises chemical and structural changes due to hydration, the nucleation and crystallization of different mineral phases at low temperatures, which can be resolved with optical methods. First experimental alteration studies of natural glass surfaces (obsidian) have been carried out using an AFM fluid cell. The cell allows in-situ observations of alteration processes along surfaces in a fluid either as a batch experiment or as a continuous flow experiment. Fresh glass surfaces were treated with sulfuric acid for different time periods at 25 deg C. Surface changes of the glass have been studied, e.g. roughness changes.
