Ancient and medieval glasses that have survived the deleterious attack of the environment for millennia have long since proposed as proxy to estimate and predict the corrosion mechanism of nuclear waste glasses. However, because both composition and environmental burial conditions vastly differ between hydrolytically less stable ancient glasses and modern advanced nuclear waste glasses, only semi-quantitative conclusions can be drawn about the likely performance of the latter as long-term stable immobilisation matrices for high-level radioactive nuclear waste. In this paper, special emphasis has been devoted to the behaviour of manganese, present as both iron decolourant and colouring ions in ancient Roman and medieval glasses. Study of the behaviour of manganese in ancient glasses during weathering may provide some limited clues to the behaviour of long-lived radioactive technetium-99. Knowledge of the corrosion kinetics of ancient glasses will allow, eventually, a reasonable prediction of the long-term performance of glassy nuclear waste forms as a function of their composition and environmental parameters, i.e. groundwater composition, flow rate, pH, solution volume, and surface area.
