Exothermic Supercooled Liquid–Liquid Transition in Amorphous Sulfur
ZHANG Dou-Dou1, LIU Xiu-Ru1**, HONG Shi-Ming1, LI Liang-Bin2, CUI Kun-Peng 2, SHAO Chun-Guang 3, HE Zhu 1, XU Ji-An4
1Laboratory of High Pressure Physics, Southwest Jiaotong University, Chengdu 610031 2National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 3National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002 4Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621000
Abstract：Amorphous sulfur (a-S) is prepared by rapidly compressing molten sulfur to high pressure. From differential scanning calorimeter measurements, a large exothermic peak has been observed around 396 K. Online wide-angled x-ray scattering spectra indicate that no crystallization occurs in the temperature range 295–453 K, suggesting that the exothermal process corresponds to an amorphous-to-amorphous transition. The transition from amorphous sulfur to liquid sulfur is further verified by the direct observation of sulfur melt at the temperature of the associated transition. This is the first time of reporting that a-S transforms to liquid sulfur directly, which has avoided a crystallization process. What is more, the transition is an exothermic and a volume expansion process.
2014, Vol. 31 
