Orientational Glasses

In this paper we present a brief conceptual introduction to orientational glasses. Orientational glasses are used to study randomly diluted molecular crystals, where crystals composed of molecules with electric multipolar moments are diluted with molecules with no orientational degrees of freedom. The disorder introduced by dilution induces a glassy state at low temperatures where the orientational degrees of freedom are in random frozen-in configurations. After a general introduction to the field, some experimental observations of the glassy state are introduced followed by a discussion of some mean field-type models applied to the quadrupolar glass. Finally, results from computer simulations are presented and discussed.