Disorder in crystalline phases of chiral glass formers 5∗CB and 8∗OCB evidenced by the low temperature heat capacity

The heat capacity of two glass formers 5∗CB and 8∗OCB, each of which has two crystalline polymorphs (phases I and II) as well as a glass phase, was determined between 0.35 K and 20 K. The T-linear term of the heat capacity becomes significant below 1 K for both glasses. The glassy crystalline phase II of 5∗CB also shows such contribution, which is consistent with the existence of a residual entropy. Unexpectedly, however, the ‘stable’ phase II of 8∗OCB shows the similar contribution, indicating that this phase is disordered, whereas the glassy crystalline phase I shows no such contribution.