Premium
Thermal relaxation of poled non‐linear optical sidechain polymers: A new, semi‐empirical model
Author(s) -
van Der Vorst Cornells P.J.M.,
van Gassel Rob A. P.
Publication year - 1995
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.19950900106
Subject(s) - relaxation (psychology) , debye , polymer , debye model , annealing (glass) , thermodynamics , materials science , exponential function , condensed matter physics , thermal , linear polymer , chemistry , physics , mathematics , mathematical analysis , composite material , psychology , social psychology
Electro‐Optic relaxation of a poled, Non‐Linear Optical sidechain polymer with T g 140°C, containing 4‐dimethylamino‐4′‐nitrostilbene (“DANS”) in the sidechains, has been studied at 120°C with and without annealing at the same temperature. The time‐dependence of the decaying EO coefficients r(t) shows a strong departure from the classical single‐exponential Debye model, especially in the unannealed samples. This departure is attributed to physical ageing, slowing down the orientational relaxation of the sidechains. The Debye model with r(t)‐r(0). exp ‐t/τ] is modified semi‐empirically by introducing a time‐dependent characteristic Debye relaxation time τ(t). Of several trial expressions, one is selected which fits the relaxation data. This is τ(τ)‐τ i +C.t b