Mode-coupling theory predicts that near the glass transition, viscosity diverges as η ~ (T - T_c)^{-γ}. Density fluctuations couple to form a self-consistent feedback loop that traps particles in cages.
The MCT critical temperature T_c is where the non-ergodicity parameter jumps discontinuously. Below T_c, particles are permanently caged — the glass state. The viscosity divergence η ~ |T-T_c|^{-γ} is the hallmark signature.