Résumé
It has been shown experimentally that Al2O3 has a great impact on the chemical durability of SiO2-B2O3-Al2O3-CaO-Na2O glasses In glasses with a low Al2O3 content, a rapid release of Si into the solution is observed, followed by a sudden stop of the glass alteration. Conversely, glasses with a higher Al2O3 content exhibit a longer period before the Si and B releases into the solution diminish.To gain deeper insights into these experimental findings, classical molecular dynamics (MD) simulations were conducted using potentials fitted to simulate SiO2-Al2O3-CaO-Na2O glasses in contact with water. Employing the Potential Mean Force method to simulate hydrolysis processes enabled us to explain the impact of Al on glass durability. Specifically, we noted that an increase in the Al2O3 content in the glass composition resulted in a substantial augmentation of hydrolysis energies within the Si local environments. Simultaneously, the energy required to reform the Si-O bonds decreased.Utilizing a new Monte Carlo approach capable of simulating glass alteration by modeling both water diffusion within the glass and hydrolysis mechanisms, various alteration scenarios were explored in SiO2-B2O3-Al2O3-Na2O glasses. The calculations suggest that a rapid release of Si into the solution can result in the formation of a Si-enriched and dense external layer, contributing to a quick reduction of the alteration rate.