Comparisons are made of the translational and rotational diffusion of small-molecule probes in a polymer near its glass transition temperature; T g . In the rubbery state; 1.1 T g > T > T g ; translational diffusion is much less temperature dependent than rotational reorientation; in a “quenched” glass; translation and rotation have similar temperature dependencies. This is explained to be a consequence of the fact that in the rubbery state near T g the breadth of the polymer relaxation distribution is strongly temperature dependent; while in the quenched glass it is temperature invariant.