Reversible Polarization Gratings on Thin Films of Polyoxetanes Bearing 4-(N,N-Diphenyl)amino-4′-nitroazobenzene Chromophores

Abstract

Polarization gratings were fabricated by the two‐beam coupling method on the surface of a series of polyoxetanes containing 4‐(N,N‐diphenyl)amino‐4′‐nitroazobenzene pendants with the azobenzene chromophores either side‐on attached or end‐on attached through short or long spacers to the main chain. The dynamics of formation of the gratings or writings was studied in relation to the diffraction efficiency. The erasing behavior of the gratings was also examined, irradiating a linearly polarized single beam. The temporal stability of the diffraction efficiency was further studied after removing the coupled excitation beam. Both the mode of attachment of the chromophore to the main chain and the length of the side‐chain spacer greatly influenced the dynamic properties of the diffraction gratings. The presence of a long side‐chain spacer and side‐on attachment of the chromophore resulted in faster writing and erasing behavior. A preliminary study by solid‐state 13C NMR of the relaxational behavior of the main‐chain CH2 groups and the pendant chromophores provided a reasonable picture to help explain the photo‐induced reorientation and relaxation of the azo chromophores at the molecular level.

Synthesis and characterization of photoactive poly(arylene ether sulfone)s containing azobenzene moieties in their main chains

“…Polymers bearing azobenzene moieties (azo-polymers) are fascinating materials and have attracted considerable attention in recent years because of their unique reversible photo-isomerization and photoinduced anisotropy properties [3][4][5][6][7][8]. The photoinduced isomerization and anisotropy can cause significant bulk, surface property variation and polarity of the polymers, such as photoinduced phase transition, photoinduced surface relief gratings (SRGs) and photoinduced birefringence [9][10][11][12][13][14][15], which show potential applications in fields such as optical data storage, optical switching and nonlinear optical materials [16][17][18][19][20][21][22][23]. In order to increase the optical stability for long-term applications, many efforts have been made to design and synthesize new high-T g aromatic azo-polymers, such as polyacrylate containing fully aromatic azo side chains and azo-polyimides.…”

Novel, side-on, PVK-based nonlinear optical polymers: Synthesis and NLO properties

“…Although very scarce, there is another type of NLO polymers (side-on type), namely, one in which the site for the introduction of the chromophore within the polymer backbone is at the centre of the p bridge [35][36][37][38]. Jen et al prepared a series of this type of side-chain dendronized NLO polymers by covalently attaching the chromophore moieties to the centre of the p-bridge in the polymeric backbone; the ensuing compounds displayed high dielectric strength, excellent optical quality, good processability, and reliable poling behaviors [39].…”

Dynamic processes of the photoinduced birefringence of two novel azobenzene‐functionalized polymers

“…Polymers bearing azobenzene moieties (azo polymers) have been considered promising materials for optical data storage, optical switches, and electrooptical modulators and in other electrooptic areas 1–5. Birefringence in azo‐polymer films may be created by trans–cis–trans photoisomerization processes produced with a linear polarized light, with the induced orientation of the chromophores being perpendicular to the polarization direction 6.…”