ilicate, trisilicate, and tetrasilicate glasses, lithium disilicate glass, and the products of their crystallization. It is
shown that these researches contribute to the development of the modern concepts regarding the mechanism of
leaching in silicate glasses and give insight into the role of water in this process and chemical structural trans-
formations occurring in glasses upon leaching. The feasibility of determining the quantitative contents of
molecular and structural water (the water formed at the sacrifice of silanol hydroxyls) in completely leached
glasses and products of their crystallization is demonstrated. The results obtained provide support for the mech-
anism of low-temperature condensation of the Si–OH groups formed in the course of leaching and for the view
that protons are involved in the reaction of ion-exchange leaching according to the scheme:
Si–O–Na+ + H+
Si–OH + Na+.