Challenging the Kauzmann paradox using an ultra-stable perfluoropolymer glass with a fictive temperature below the dynamic VFT temperature.

ABSTRACT: Ultra-stable fluoropolymer glasses were created using vacuum pyrolysis deposition that show large fictive temperature T_f reductions relative to the glass transition temperature T_g of the rejuvenated material. T_f was also found to be 11.4 K below the dynamic VFT temperature T_VFT. 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_f reduction of 62.6 K relative to the T_g 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_K for the material as related to T_VFT. 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_f < T < T_g).

SUBMITTER: El Banna AA 

PROVIDER: S-EPMC10014873 | biostudies-literature | 2023 Mar

REPOSITORIES: biostudies-literature