Full Paper Macromolecular Chemistry and Physics (1 of 10) 1700127 © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com DOI: 10.1002/macp.201700127 Photo-Orientation Phenomena in Photochromic Liquid Crystalline Azobenzene-Containing Polymethacrylates with Different Spacer Length Alexey Bobrovsky,* Valery Shibaev, Alexey Piryazev, Denis V. Anokhin, Dimitri A. Ivanov, Olga Sinitsyna, Vera Hamplova, Miroslav Kaspar, Alexej Bubnov Synthesis and investigation of the phase behavior and photo-optical properties of two chiral liquid-crystalline polymers with azobenzene-containing side groups having different spacer lengths, 6 and 10 methylene groups (PMAzo-6 and PMAzo-10, respectively) are described. Formation of different smectic phases and high-temperature cholesteric phase is studied by polarizing optical microscope, differential scanning calorimetry, and X-ray investigations. It is shown that UV-irradiation induces effective reversible E–Z photoisomerization in polymer solutions and films. Atomic force microscopy (AFM) study reveals substantial changes in the surface topography of the polymer PMAzo-6 film after UV-irradiation, whereas PMAzo-10 sur- face remains the same. Irradiation by polarized light (457 nm) results in photo-orientation pro- cess in polymer films consequential in significant alignment of the chromophores in direction perpendicular to the polari- zation plane of the incident light. A significant difference is found in thermal stability of the photoinduced alignment; an annealing of PMAzo-10 irradiated samples results in a slight decrease of dichroism values (down to 0.57); whereas the dichroism increases up to very high values (0.91) for PMAzo-6. Prof. A. Bobrovsky, Prof. V. Shibaev, Dr. O. Sinitsyna Faculty of Chemistry Moscow State University Leninskie gory, Moscow 119991, Russia E-mail: bbrvsky@yahoo.com A. Piryazev, Dr. D. V. Anokhin, Prof. D. A. Ivanov Faculty of Fundamental Physical and Chemical Engineering Moscow State University Leninskie gory, Moscow 119991, Russia Dr. D. V. Anokhin Institute of Problems of Chemical Physics RAS Semenov Prospect 1 Chernogolovka, Moscow region 142432, Russia Prof. D. A. Ivanov Institut de Sciences des Matériaux de Mulhouse CNRS UMR 7361, Jean Starcky 15, F-68057 Mulhouse France Dr. V. Hamplova, Dr. M. Kaspar, Dr. A. Bubnov Institute of Physics The Czech Academy of Sciences 182 21 Prague 8, Czech Republic 1. Introduction Photochromic liquid-crystalline (LC) polymers repre- sent a promising type of smart materials with high potential for a large variety of applications in optics and optoelectronics. [1,2] Among different types of photochromic fragments incorporated in polymer matrices, the azoben- zene moieties are the most remarkable chromophores Macromol. Chem. Phys. , DOI: 10.1002/macp.201700127