Photoinduced birefringence of novel azobenzene poly(esterimide)s; the effect of chromophore substituent and excitation conditions

Thermal, optical and photoinduced properties of a series of homo and co-polyimides with two kinds of covalently bonded azo-dyes and their supramolecular counterparts

“…Moreover, the supramolecular systems based on H-bonds were characterized by a faster growth of the Dn than analogue functionalized polymers. Low values of the Dn and a high relaxation of photoinduced birefringence of polymers containing azo-chromophores bonded by flexible chain indicates, that more promising materials for induction of the Dn are azo-polymers containing covalently bonded choromophores, where one of the aromatic rings is incorporated to the main-chain of the polymer [56,57]. The influence of a kind of connection of chromophore and a kind of polymer matrix was clearly observed by using the irradiation wavelength of 445 nm, when only the DR13 azochromophore was excited.…”

Poly(esterimide) bearing azobenzene units as photoaligning layer for liquid crystals

“…The details of synthesis, characterization, optical and thermal properties together with the photoinduced birefringence of the studied polymer has been reported recently [17]. The chemical structure of used poly(esterimide) (PESI-F) is presented in Fig.…”

“…The utilized azopolymer has been chosen basing on the recent results showing its high glass transition temperature, low birefringence relaxation in the dark and good, as for polyimides, solubility [17]. The anisotropy in the PESI-F thin film was induced by UV linearly polarized light.…”

Photo-Orientation Phenomena in Photochromic Liquid Crystalline Azobenzene-Containing Polymethacrylates with Different Spacer Length

“…[5][6][7][8][9][10][11][12] From the other hand, an action of polarized light induces photo-orientation processes and alignment of chromophores in direction perpendicular to the polarization plane of the incident light. [13][14][15][16][17][18][19][20] Another interesting direction of the research is connected with investigation of the surface topography of LC polymer systems and, especially, manipulation of surface relief by light irradiation. In a number of previous works, the ability of light control of surface topography has been demonstrated.…”

“…Photoisomerization of azobenzene fragments in LC media enables to realize isothermal phase transitions . From the other hand, an action of polarized light induces photo‐orientation processes and alignment of chromophores in direction perpendicular to the polarization plane of the incident light …”