Ultra-stable fluoropolymer glasses were created using vacuum pyrolysis deposition that show large fictive temperature T reductions relative to the glass transition temperature T of the rejuvenated material. T was also found to be 11.4 K below the dynamic VFT temperature T. Glass films with various thickness (200-1150 nm) were deposited onto different temperature substrates. Glassy films were characterized using rapid-chip calorimetry, Fourier-transform infrared spectroscopy and intrinsic viscosity measurements. Large enthalpy overshoots were observed upon heating and a T reduction of 62.6 K relative to the T of 348 K was observed. This reduction exceeds values reported for a 20-million-year-old amber and another amorphous fluoropolymer and is below the putative Kauzmann temperature T for the material as related to T. These results challenge the importance of the Kauzmann paradox in glass-formation and illustrates a powerful method for the exploration of material dynamics deep in the glassy state (T < T < T).
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10014873 | PMC |
http://dx.doi.org/10.1038/s41598-023-31074-0 | DOI Listing |
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