Rigidity and logarithmic relaxation in network glasses

We propose a microscopic theory of relaxation of glass under pressure. We show how increased rigidity of the glass structure under pressure couples to local densification events to yield slow logarithmic relaxation and relate the microscopic parameters of the theory to the experimental densification data. We discuss two regimes of slow relaxation, one of which is the relaxation in the structure where rigidity percolates. Finally, we suggest that coupling of local densification events to structural rigidity can describe a wider range of relaxations in disordered media.