We report on the temperature, pressure, and time (T, p, and t)-dependent features of thermal conductivity, κ, of partially ordered, non-equilibrium state of C₆₀-OG, the orientational glass of Buckminsterfullerene (at T below the orientational freezing temperature T_og) made more unstable (i) by partially depressurizing its high-p formed state to elastically expand it and (ii) by further pressurizing that state to elastically contract it. The sub-T_og effects observed on heating of C₆₀-OG differ from those of glasses because phonon propagation depends on the ratio of two well-defined orientational states of C₆₀ molecules and the density of the solid. A broad peak-like feature appears at T near T_og in the κ-T plots of C₆₀-OG formed at 0.7 GPa, depressurized to 0.2 GPa and heated at 0.2 GPa, which we attribute to partial overlap of the sub-T_og and T_og features. A sub-T_og local minimum appears in the κ-T plots at T well below T_og of C₆₀-OG formed at 0.1 GPa, pressurized to 0.5 GPa and heated at 0.5 GPa and it corresponds to the state of maximum disorder. Although Buckminsterfullerene is regarded as an orientationally disordered crystal, variation of its properties with T and p is qualitatively different from other such crystals. We discuss the findings in terms of the nature of its disorder, sensitivity of its rotational dynamics to temperature, and the absence of the Johari-Goldstein relaxation. All seem to affect the phenomenology of its glass-like transition.

中文翻译：

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巴克敏斯特富勒烯的压力致密化和弹性改变的定向玻璃的不稳定性和热导率

我们报告了温度，压力和时间（T，p和t）依赖的热导率κ的特征，C ₆₀ -OG是部分取向的Buckminsterfullerene取向玻璃（在T下方，取向冻结温度T _og）变得更加不稳定（i）通过部分地降低其高p形成状态以使其弹性膨胀，以及（ii）进一步对该状态进行加压以使其弹性收缩而变得更加不稳定。子Ť _OG效果上的C观察到加热₆₀-OG与玻璃的区别在于，声子的传播取决于C ₆₀分子两个明确定义的取向态之比和固体的密度。的宽峰状在特征出现Ť邻近Ť _OG在κ-T的C曲线₆₀在0.7 GPA形成-OG，减压至0.2 GPA和0.2 GPA，我们属性的子部分重叠加热Ť _OG和Ť _OG特征。一分牛逼_OG当地最低出现在κ -牛逼地块在牛逼远低于牛逼_OG在₆₀ ℃下以0.1GPa形成C ₆₀ -OG，加压至0.5GPa并以0.5GPa加热，这对应于最大无序状态。尽管巴克敏斯特富勒烯被认为是取向无序的晶体，但其性质随T和p的变化与其他此类晶体在质上有所不同。我们根据疾病的性质，旋转动力学对温度的敏感性以及Johari-Goldstein弛豫的缺乏来讨论这些发现。所有这些似乎都影响了其玻璃状转变的现象学。