Epoxy-based polymers functionalized with bisazo chromophores: Synthesis, characterization and photoresponsive behavior

Liquid-crystalline compounds containing both a strong push–pull azo chromophore and a cholesteryl unit as photoresponsive molecular glass materials

“…Even a slight increase in the birefringence can be observed after switching off the irradiating light, which has also been observed for other amorphous molecular materials with a linear molecular structure. [2,4,5,33,38] The low orientational order parameters of NT-Chol could be attributed to the same reasons discussed above. Figure 5 gives the polar plots of the relative infrared absorbance of the stretching vibration bands of ν(C=C, aromatic) for the R-Chol films, which are 1599 cm -1 for CA-Chol, 1597 cm -1 for CN-Chol, and 1601 cm -1 for NT-Chol.…”

“…[2,4,5,33,36,[38][39][40] In contrast to the typical decay relaxation, no birefringence decrease is observed for CA-Chol and CN-Chol after switching off the irradiating light (Figure 4). [2,4,5,33,36,[38][39][40] In contrast to the typical decay relaxation, no birefringence decrease is observed for CA-Chol and CN-Chol after switching off the irradiating light (Figure 4).…”

“…Before the excitation laser was switched on, no transmittance of the probing laser beam can be detected by the photodiode, because the sample placed between the crossed polarizers is isotropic. [31,32,36,38] It reflects the influence of the electron-withdrawing groups on the photoinduced orientation ability at the molecular level. As homeotropical alignment is typical in smectic LC, the predominant orientational direction of the mesogenic groups could be perpendicular to the substrate surface.…”

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

“…However, as it was shown recently, that knowledge of the optical response dependence on the writing wavelength is very precious since it allows for a proper selection of the excitation conditions that ensures the highest rate of the birefringence growth or the highest birefringence level [20,21].…”

Photoinduced deformation behavior of a series of newly synthesized epoxy-based polymers bearing push–pull azo chromophores

“…A variety of epoxy-based azo polymers with the same backbone structure have been synthesized by postpolymerization azo-coupling reactions based on a precursor polymer, which was obtained by the reaction between BP and aniline [50]. The BP-based polymers obtained from the postpolymerization modification have been used to investigate the nonlinear optical (NLO) properties [50], photoinduced SRG formation [29,31], and photoinduced colloid deformation [44,45]. Besides the monomer BP, 1,4-cyclohexanedimethanol diglycidyl ether (CH) is among the few epoxy monomers that has been used to prepare epoxy-based azo polymers [24,51].…”