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Current issue   Ukr. J. Phys. 2014, Vol. 58, N 12, p.1138-1142
doi:10.15407/ujpe58.12.1138    Paper

Kurioz Yu.I.

Institute of Physics, Nat. Acad. of Sci. of Ukraine
(46, Prosp. Nauky, Kyiv 03680, Ukraine; e-mail: kurioz@iop.kiev.ua)

Phototransformations in Cellulose Cinnamate Films at Illumination with Polarized UV Light

Section: Soft matter
Original Author's Text: Ukrainian

Abstract: Light-induced changes in photosensitive organic polymer films based on cellulose cinnamate have been studied. Film specimens illuminated with polarized UV light are found to become anisotropic. The dependence of the birefringence in the polymer film on the illumination time is measured, and the difference between the refractive indices for the extraordinary and ordinary waves is found to have a maximum. The constant and dynamic anisotropy components are found to exist in the films under illumination, and they are driven by different recording mechanisms. The relaxation process in the films after their UV illumination has been switchedoff can be described by an exponential dependence with the characteristic times typical of the cis-trans isomerization. The mechanism of photodimerization is found to be responsible for the existence of a constant anisotropy component.

Key words: photosensitive polymers, anisotropy, photoalignment.