Figure 1. Data from solution analyses.

Time evolution of the solution pH (a), the concentration of Si, ²⁹Si/²⁸Si and ²⁹Si/³⁰Si ratios (b), the equivalent thickness of altered glass (ETh) calculated from B release into solution (c) and the glass dissolution rate (d). The pH_90 °C was maintained at 7±0.25 by regular additions of diluted HNO₃. Boron was used to calculate glass corrosion thickness and rate. This element is known to be a good corrosion tracer as it is very soluble and only slightly retained in the alteration layer (as verified by ToF-SIMS and EFTEM analyses).