Colloquium

Monday 14 November 2022

Speaker

Daniele Cangialosi

Affiliation

Centro de Fisíca de Materiales (CFM/CSIC) and Donostia International Physics Center (DIPC), San Sebastian, Spain

Title

Enlarging polymer free interface to access low energy glasses

Location

online.

Time

16:00

Language

English

Abstract

Approach to equilibrium in glasses, so-called physical aging, is generally described as assisted exclusively by the main α relaxation. As a result, the evolution of the thermodynamic state below but close to the glass transition temperature, Tg, exhibits monotonous decay towards equilibrium. In this contribution, I will show that, if physical aging is carried out significantly below Tg and for prolonged time, glasses of different nature, including polymers, metallic glasses and low molecular weight glass formers, approach equilibrium via at least two steps.(1) While the slower equilibration step exhibits standard α relaxation behavior, fast equilibration mechanisms are mildly activated and, therefore, their action survives way below Tg. Importantly, enlarging the amount of glassy sample free interface allows reducing the time scale of equilibration via fast mechanisms, thereby providing accelerated access to low energy states. Specifically, aging of polymer films and nanospheres, when conducted in appropriate conditions, may convey these glasses to energy states low enough to identify the transformation from standard to ideal glass, (2,3) theorized long ago.

1. D. Cangialosi, V.M. Boucher, A. Alegría, J. Colmenero, Phys. Rev. Lett. 111 (2013) 095701
2. D. Cangialosi, V.M. Boucher, A. Alegría, J. Colmenero, Phys. Chem. Chem. Phys 19 (2017) 961
3. X. Monnier, J. Colmenero, M. Wolf, D. Cangialosi, Phys. Rev. Lett. 126 (2021) 118004