Supercritical Conversion of the Third Blue Phase to the Isotropic Phase in a Highly Chiral Liquid Crystal

The results of two independent experiments in the vicinity of the “transition” from the third blue phase ( ${\mathrm{BP}}_{\mathrm{III}}$) to isotropic phase ( $I$) are reported for a highly chiral liquid crystal. Heat capacity measurements using a high-resolution calorimeter and dynamic light-scattering measurements using circularly polarized light have been performed. The data show a continuous evolution of ${\mathrm{BP}}_{\mathrm{III}}$ into $I$ with no critical fluctuations. This is strong evidence that the ${\mathrm{BP}}_{\mathrm{III}}$-I transition in this compound is supercritical, indicating that the ${\mathrm{BP}}_{\mathrm{III}}$ and I phases possess the same macroscopic symmetry.