Powell C Travis, Paeng Keewook, Chen Zhen, Richert Ranko, Yu Lian, Ediger M D
Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.
J Phys Chem B. 2014 Jul 17;118(28):8203-9. doi: 10.1021/jp501301y. Epub 2014 Apr 3.
Crystal growth kinetics and liquid dynamics of 1,2-diphenylcyclopentene (DPCP) and 1,2-diphenylcyclohexene (DPCH) were characterized by optical microscopy and dielectric spectroscopy. These two molecules are structurally homologous and dynamically similar to the well-studied glassformer ortho-terphenyl (OTP). In the supercooled liquid states of DPCP and DPCH, the kinetic component of crystal growth ukin has a power law relationship with the primary structural relaxation time τα, ukin [proportionality] τα(–ξ) (ξ ≈ 0.7), similar to OTP and other fragile liquids. Near the glass transition temperature (Tg), both DPCP and DPCH develop much faster crystal growth via the so-called GC (glass to crystal) mode, again similar to the behavior of OTP. We find that the α-relaxation process apparently controls the onset of GC growth, with GC growth possible only at sufficiently low fluidity. These results support the view that GC crystal growth can only occur in systems where the liquid and crystal exhibit similar local packing arrangements.
通过光学显微镜和介电谱对1,2 - 二苯基环戊烯（DPCP）和1,2 - 二苯基环己烯（DPCH）的晶体生长动力学和液体动力学进行了表征。这两种分子在结构上是同源的，并且在动力学上与研究充分的玻璃形成剂邻三联苯（OTP）相似。在DPCP和DPCH的过冷液态中，晶体生长的动力学成分ukin与主要结构弛豫时间τα具有幂律关系，ukin ∝ τα(–ξ)（ξ ≈ 0.7），这与OTP和其他易碎液体相似。在接近玻璃化转变温度（Tg）时，DPCP和DPCH都通过所谓的GC（玻璃到晶体）模式实现了快得多的晶体生长，这同样与OTP的行为相似。我们发现α弛豫过程显然控制着GC生长的起始，只有在足够低的流动性下才可能发生GC生长。这些结果支持了这样一种观点，即GC晶体生长只能发生在液体和晶体表现出相似局部堆积排列的系统中。
