Fluctuating Spinodal-like Structure in the Glacial\nPhase of d‑Mannitol

The\nglacial phase can be formed from supercooled liquid (SCL) in\ncertain systems, which is called liquid–liquid transition (LLT).\nRevealing the nature of the glacial phase especially in a single-component\nsystem is crucial for understanding the LLT process. Here, by using\nflash differential scanning calorimetry and cold-field transmission\nelectron microscopy, the structure of the d-mannitol glacial\nphase and the phase transition kinetics between the glacial phase\nand SCL were studied. We found that the glacial phase is a fluctuating\nspinodal-like structure. And the glacial phase displays a first-order\nmelting characteristic when it transforms into the SCL. Furthermore,\nthe LLT diagram in the enthalpy-temperature coordinate system is constructed\nbased on the nucleation–growth and spinodal-decomposition transitions.\nOur findings provide new insight into the LLT process of the glass\nforming liquids.