Stabilized nonlinear optical chromophore alignment in high- guest - host polycarbonates

Content Provider	Scilit
Author	Healy, D. Bloor, D. Gray, D. Cross, G. H.
Copyright Year	1997
Description	Journal: Journal of Physics D: Applied Physics Electric-field-poling studies of two polycarbonates doped with 2-(N,N dimethylamino)-5-nitroacetanilide revealed a long-term room-temperature alignment stability. This stability at room temperature is compared with that of similarly doped poly(methyl methacrylate) (PMMA) which displays short-term relaxation. Despite several previous suggestions that hydrogen bonding between guest and host plays a major role in these effects, infra-red spectroscopic studies refuted the idea that stronger hydrogen bond formation in the polycarbonate rather than in PMMA is the dominant influence. Rather we show, using an examination of the poling currents during poling, that the re-orientation dynamics in the polycarbonate systems are markedly different. In the case of PMMA-doped films, the deposited surface charge is compensated by poling currents at a rate at least comparable to the rate of deposition of corona charge. The compensation rate for polycarbonate-doped systems was markedly lower, however, suggesting that polar re-orientation is slower. Studies of the second-order optical nonlinearities of poled thin films using second-harmonic generation revealed an apparent enhancement of the second-harmonic coefficient compared with the predictions of conventional theories. However, we note that the use of microscopic parameters (the dipole moment and the first hyperpolarizability) obtained from measurements in non-dipolar media may give rise to the apparent anomaly since high reaction fields in polycarbonate films may act to modify these parameters.
Related Links	http://iopscience.iop.org/article/10.1088/0022-3727/30/22/004/pdf
Ending Page	3084
Page Count	6
Starting Page	3079
ISSN	00223727
e-ISSN	13616463
DOI	10.1088/0022-3727/30/22/004
Journal	Journal of Physics D: Applied Physics
Issue Number	22
Volume Number	30
Language	English
Publisher	IOP Publishing
Publisher Date	1997-11-21
Access Restriction	Open
Subject Keyword	Journal: Journal of Physics D: Applied Physics Atomic, Molecular and Chemical Physics Second Harmonic Generation Second Order Hydrogen Bond Infra Red Electric Field Nonlinear Optics Thin Film Room Temperature Second Harmonic
Content Type	Text
Resource Type	Article
Subject	Surfaces, Coatings and Films Acoustics and Ultrasonics Condensed Matter Physics Electronic, Optical and Magnetic Materials