Glass transition in single-crystal<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mrow><mml:mn>60</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>studied by high-resolution dilatometry

Abstract

The thermal expansion of single-crystalline ${\mathrm{C}}_{6}$ is studied using high-resolution capacitance dilatometry. In addition to the orientational-ordering transition at 261 K, we observe a transition at ${\mathit{T}}_{\mathit{g}}$\ensuremath{\approxeq}90 K due to the freezing in of orientational disorder, which has the character of a glass transition. The relaxation near ${\mathit{T}}_{\mathit{g}}$ is studied by varying the heating (cooling) rate over more than two decades. It is found to obey an Arrhenius behavior with ${\mathit{E}}_{\mathit{a}}$=288\ifmmode\pm\else\textpm\fi{}5 meV within a simple glass-transition model.