Poling dynamics and investigation into the behavior of trapped charge in poled polymer films for nonlinear optical applications

Mark A Pauley, H. W. Guan, C. H. Wang

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

The behavior of surface and trapped charge that originate during contact electric-field poling of a model guest-host nonlinearly active polymer has been investigated. Charge effects in thin films of para-nitroaniline doped polymethylmethacrylate were studied during and after the poling process by simultaneous measurement of the current through the poling circuit and the second harmonic generation (SHG) signal from the polymer system. The poling current present in a fresh sample was found to differ in both magnitude and temporal dependence to that observed in the sample during subsequent polings. The magnitude of the steady-state current eventually reached during the poling process was found to depend on temperature and is related to the mobility of charge. A sharp drop-off in SHG signal intensity that occurred when the poling electrodes were grounded is shown to result from the removal of surface charge that orients chromophore dipoles near the surface of the film; the decay in the macroscopic polarization that then occurs is prolonged by charges trapped in the polymer matrix. The build-up of trapped charge explains a memory effect in which the SHG signal relaxation time gradually increased as the film was subjected to multiple polings until a steady-state value was reached. Finally, it is demonstrated that the charges trapped in the polymer matrix are released only after the polymer is heated to high above its temperature of glass transition and the SHG signal has completely decayed away.

Original languageEnglish (US)
Pages (from-to)6834-6842
Number of pages9
JournalJournal of Chemical Physics
Volume104
Issue number17
DOIs
StatePublished - Jan 1 1996

Fingerprint

Harmonic generation
Polymer films
harmonic generations
Polymers
polymers
Polymer matrix
Polymethyl Methacrylate
Chromophores
Surface charge
Relaxation time
Glass transition
matrices
Electric fields
chromophores
Polarization
electric contacts
Data storage equipment
Thin films
Temperature
Electrodes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Poling dynamics and investigation into the behavior of trapped charge in poled polymer films for nonlinear optical applications. / Pauley, Mark A; Guan, H. W.; Wang, C. H.

In: Journal of Chemical Physics, Vol. 104, No. 17, 01.01.1996, p. 6834-6842.

Research output: Contribution to journalArticle

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