The glass transition is marked by tremendous increase in viscosity over a small increase in density / decrease in temperature. However the fundamental Stokes-Einstein and Debye equations that relate translation and rotation degrees in fluids, show a breakdown approaching the glass transition.

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Using a colloidal glass with anisotropic dimers as trancers, we show that this breakdown is shape dependent. Smaller dimers can rotate much easier than longer ones at high density. Our results highlight the importance of effectively steric interactions in glassy properties.

S Vivek, ER Weeks Decoupling of translational and rotational diffusion in quasi-2D colloidal fluids arXiv:1707.06160

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