9. Conclusion

Borosilicate glasses subjected to weathering by natural waters with low renewal rates weather very slowly. Their weathering mechanisms are both complex and interrelated: depending on the weathering conditions, velocity regimes can be very different, even though the basic mechanisms are the same. It is therefore essential to quantify the mechanisms themselves, rather than simply using standardized experimental determination of a weathering rate value, if we are to be able to extrapolate from experimental laboratory measurements to long-term weathering conditions in the natural environment.

As a result, very precise techniques are needed to quantify this alteration and extrapolate it over the very long term, both in terms of monitoring solution analyses, which enable us to trace alteration rates, and of observing alteration products, which enable us to understand...