The Effect of Molecular Structure on Borosilicate Glass Leaching

The leaching behavior of several sodium borosilicate glasses has been characterized using a combination of pH stat titrations, elemental solution analyses, elemental depth profiling via elastic recoil detection analysis and Rutherford backscattering, sodium diffusion measurements, and 11B NMR measurements on both leached and unleached glass. Leaching results indicate that the molecular structure of the glass controls glass dissolution by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sitas. There is no correlation between sodium leaching and sodium diffusion in the unaltered glass. For most borosilicates in most environments, network hydrolysis controls the kinetics of glass dissolution