Abstract

Infrared spectroscopy has been coupled with the polarization modulation technique in order to characterize the molecular orientation in films of azopolymers irradiated <i>in situ</i> with polarized visible light. The results obtained on disperse red 1-containing amorphous azopolymer (pDR1A) demonstrate the high efficiency of polarization modulation infrared linear dichroism to determine quantitatively the time dependence of the orientation function of several chemical groups during the orientation (laser on) and relaxation (laser off) processes. The difference dichroic spectra show that polarized visible light induces a preferential orientation of the azobenzene groups perpendicular to the direction of the polarization of the writing laser. This orientation of the side chains also results in a slight cooperative orientation of the C=O ester groups of the main chain of the polymer. The time dependence of the orientation function shows that the orientation and relaxation processes could be described by a biexponential function involving "fast" and "slow" response modes. The rate constants associated with these modes are the same for the main chain and the side chains of the polymer. Finally, we have observed that the level of orientation and the rate constants of the orientation and relaxation processes depend strongly on the film thickness.

Light-induced orientation in a high glass transition temperature polyimide with polar azo dyes in the side chain

Zouheir Sekkat, Jonathan Wood, Emil F. Aust, Wolfgang Knoll, Willi Volksen, and Robert D. Miller
J. Opt. Soc. Am. B 13(8) 1713-1724 (1996)

Nanoporous-template-modulated azopolymers for enhancing reversible photo-transformation

Lihong Kang, Shencheng Fu, Xintong Zhang, Xinnong Wang, Jiarui Wu, Shuangyan Liu, Ruiya Ji, Xiuxiu Han, Yichun Liu, and Jinhuan Li
OSA Continuum 1(2) 477-487 (2018)

Fabrication of a pure polarization grating in a cross-linked azopolymer by polarization-modulated holography

Jingli Zhou, Jing Shen, Jianjun Yang, Yan Ke, Keyi Wang, and Qijin Zhang
Opt. Lett. 31(10) 1370-1372 (2006)

Anisotropic hybrid organic/inorganic (azopolymer/SiO₂ NP) materials with enhanced photoinduced birefringence

Dimana Nazarova, Lian Nedelchev, Peter Sharlandjiev, and Violeta Dragostinova
Appl. Opt. 52(22) E28-E33 (2013)

Instantaneous photoinduced patterning of an azopolymer colloidal nanosphere assembly

Ewelina Ortyl, Sonia Zielinska, Régis Barillé, Yasser Almohamed, and Jean-Michel Nunzi
Opt. Mater. Express 6(9) 2925-2932 (2016)