Water Dynamics in Nanoporous Alteration Layer Coming from Glass Alteration: An Experimental Approach

Protons dynamics in borosilicate glasses of various compositions (SiO2/B2O3/NaO/CaO/X, with X = Al2O3 or ZrO2) at various stages of alteration have been characterized at a picosecond scale using quasielastic neutron scattering (QENS). The results obtained were compared to the one from porous silica-based material (MCM41) having pore wall surfaces with Si–OH, Al–OH, or Zr–OH terminal groups and pore sizes around 2.3 nm. The composition and the nanoporosity of the alteration layers were characterized using solution analysis, small angle X-ray scattering and transmission electron microscopy. The strength hydrogen bonds of confined water were studied using thermogravimetric analysis and differential thermal analysis. The results showed that the free water bonding and the mobility of protons depend on the altered glass composition and that the residence time of water obtained from QENS analysis is apparently correlated to the alteration rate of the glass. Moreover, whereas the composition of the alteration lay...