Diffusionless crystal growth from glass has precursor in equilibrium liquid.
A remarkable property of certain glass-forming liquids is that a fast mode of crystal growth is suddenly activated near the glass transition temperature, Tg, and continues in the glassy state. This mode of growth, termed GC (glass-crystal), is so fast that it is not limited by molecular diffusion in the bulk liquid. We have studied the GC growth by growing multiple crystal polymorphs from the liquid of ROY, currently the top system for the number of coexisting polymorphs of known structures. We observed a new feature of GC growth that conflicts with its current description in the literature. We found that the GC mode is not truly a new growth mode suddenly appearing near Tg but one already existing in the equilibrium liquid up to approximately 1.15 Tg, in the form of fast-growing fibers. This finding is relevant to testing different explanations for GC growth and favors the view that GC growth is enabled by molecular motions that are native to the glass but still persist in the viscous liquid.
Sun
Ye
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Xi
Hanmi
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Ediger
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MD
Yu
Lian
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D003460:Crystallization; D004058:Diffusion; D005898:Glass / Q000737:chemistry*; D007700:Kinetics; D044367:Phase Transition; D012996:Solutions / Q000737:chemistry*; D013696:Temperature; D013876:Thiophenes / Q000737:chemistry*; D014783:Viscosity
C429326:5-methyl-2-((4-methyl-2-nitrophenyl)amino)-3-thiophenecarbonitrile; D012996:Solutions; D013876:Thiophenes