Abatract-Combmatlon of concentration profihng wrath electrochenucal expenments yielded timedependent local ion htnbuhons 1x1 subsurface ranges of oxldlc glasses and mformatlon on the dynamics of glass corrosion In solutions, the first step of corrosion 1s based on the phase boundary eqmhbnum of glass surface groups urlth ions m the solution, whose actmties determine, besides the potential of the glass, then relative concentrations bound to the surface groups The resultmg concentration gradients below the glass surface cause an mterdtffuslon of these ions agamst the ions of the glass, which 1s either a proton/alkali ion mterdlffuslon accompamed by a hydrolytic attack and mssolutlon of the glass network and resultmg m a steady state leached layer and m mcongruent glass dlssoluaon or an alkah/alkah mterddTunon wth congruent glass &ssolutlon Corrosion m wet gases IS tierent m that the products resulting from the mterdlffuslon are accumulated at the surface and the network IS not dissolved so that an ion-exchanged layer ~th growmg thickness develops The mechanisms are presented for a general understanding of glass corroston and may help to select approprtate substrate glasses and thetr modes of storage and cleaning, whuzh depend on the requirements of the coatmgs