Glass transition in hard disc mixtures

Binary hard disc mixtures show eutectic freezing when the diameters differ by more than 30% and near the eutectic composition glasses can be formed wi thout complications due to freezing. The glasses are characterized by measu ring their equation of state and entropy. The glass transition is described by including the fluid and its many glasses within a unified formalism tha t represents the fluid as the collection of all its glasses. This leads to an equation of state that describes the fluid and the glasses from the idea l-gas, low-density limit to an ideal-glass high-density limit, with an idea l glass transition, where the heat capacity decreases sharply. The ideal tr ansition is pre-empted by a kinetic glass transition that occurs when the r oot-mean-squared displacement of discs, on the simulation time scale, is co mparable to a disc diameter. (C) 1999 American Institute of Physics. [S0021 -9606(99)50208-0].