Low temperature aging in a molecular glass : The case of: Cis -methyl formate
Cassidy, Andrew ; Jørgensen, Mads R.V. LU
; Glavic, Artur
; Lauter, Valeria
; Plekan, Oksana
and Field, David
(2021)
In Physical Chemistry Chemical Physics
23(29).
p.15719-15726
- Abstract
Glassy films of cis-methyl formate show spontaneous dipole orientation on deposition from the vacuum, the so-called 'spontelectric effect', creating surface potentials and electric fields within the films. We follow the decay of these fields, and their accompanying dipole orientation, on the hours timescale at deposition temperatures between 40 K and 55 K. Our data trace the low temperature 'secondary decay' mechanism, at tens of degrees below the glass transition temperature of 90 K. We show that secondary decay is due to molecular rotation, with associated activation energies lying between 0.1 and 0.2 eV. Diffusion is absent, as established from published neutron reflectivity data. Using an analytical model for the spontelectric... (More)
Glassy films of cis-methyl formate show spontaneous dipole orientation on deposition from the vacuum, the so-called 'spontelectric effect', creating surface potentials and electric fields within the films. We follow the decay of these fields, and their accompanying dipole orientation, on the hours timescale at deposition temperatures between 40 K and 55 K. Our data trace the low temperature 'secondary decay' mechanism, at tens of degrees below the glass transition temperature of 90 K. We show that secondary decay is due to molecular rotation, with associated activation energies lying between 0.1 and 0.2 eV. Diffusion is absent, as established from published neutron reflectivity data. Using an analytical model for the spontelectric effect, data are placed on a quantitative footing, showing that angular motion in excess of 50° reproduces the observed values of activation energies. Exploitation of the spontelectric effect is new in the study of glass aging and is shown here to give insight into the elusive processes which take place far from the molecular glass transition temperature. This journal is
(Less)
- author
- Cassidy, Andrew
; Jørgensen, Mads R.V.
LU
; Glavic, Artur
; Lauter, Valeria
; Plekan, Oksana
and Field, David
- organization
- publishing date
- 2021
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Chemistry Chemical Physics
- volume
- 23
- issue
- 29
- pages
- 8 pages
- publisher
- Royal Society of Chemistry
- external identifiers
-
- scopus:85111636182
- pmid:34279530
- ISSN
- 1463-9076
- DOI
- 10.1039/d1cp01332g
- language
- English
- LU publication?
- yes
- id
- 2b9cd6a0-59a0-41ac-a1e0-5f8274071a2a
- date added to LUP
- 2021-08-26 14:40:37
- date last changed
- 2024-04-20 10:12:29
@article{2b9cd6a0-59a0-41ac-a1e0-5f8274071a2a,
abstract = {{<p>Glassy films of cis-methyl formate show spontaneous dipole orientation on deposition from the vacuum, the so-called 'spontelectric effect', creating surface potentials and electric fields within the films. We follow the decay of these fields, and their accompanying dipole orientation, on the hours timescale at deposition temperatures between 40 K and 55 K. Our data trace the low temperature 'secondary decay' mechanism, at tens of degrees below the glass transition temperature of 90 K. We show that secondary decay is due to molecular rotation, with associated activation energies lying between 0.1 and 0.2 eV. Diffusion is absent, as established from published neutron reflectivity data. Using an analytical model for the spontelectric effect, data are placed on a quantitative footing, showing that angular motion in excess of 50° reproduces the observed values of activation energies. Exploitation of the spontelectric effect is new in the study of glass aging and is shown here to give insight into the elusive processes which take place far from the molecular glass transition temperature. This journal is </p>}},
author = {{Cassidy, Andrew and Jørgensen, Mads R.V. and Glavic, Artur and Lauter, Valeria and Plekan, Oksana and Field, David}},
issn = {{1463-9076}},
language = {{eng}},
number = {{29}},
pages = {{15719--15726}},
publisher = {{Royal Society of Chemistry}},
series = {{Physical Chemistry Chemical Physics}},
title = {{Low temperature aging in a molecular glass : The case of: Cis -methyl formate}},
url = {{http://dx.doi.org/10.1039/d1cp01332g}},
doi = {{10.1039/d1cp01332g}},
volume = {{23}},
year = {{2021}},
}