A theory for a certain crossover in relaxation phenomena in glasses

It is shown that the simplified mode coupling theory for supercooled liquid dynamics allows for a scenario where a first component of the system is within an ideal glass state while the second component exhibits a crossover from an ideal glass state to a state of almost liquid behaviour. The dynamics near the crossover is governed by two relevant control parameters and it can be described by a scaling law. There appear fractal spectra. Under certain simplifying assumptions or symmetry conditions the crossover becomes an ergodic to non-ergodic transition, where the Edwards-Anderson parameter of the second component changes continuously from zero to a non-zero value.