Synthesis, characterization and nonlinear optical properties study of polymers based on coloured monomers (original) (raw)
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Synthesis and characterization of polymers for nonlinear optical applications
2003
A difunctional NLO Azo-Dye chromophore has been synthesized and polymerization has been performed with a comonomer bearing a side-chain epoxy group. Deposition of the polymer on glass substrates was performed by spin-coating, resulting in uniform films up to 2 μm thickness. The orientation of the chromophore was performed under a "pin-to-plane" positive corona discharge followed by a heat- treatment in order to obtain reticulation of the films. Molecular orientation has been investigated using UV-Vis. and Raman spectroscopy. Poling of the films results in a decay of absorbance as well as in a blue shift of the spectrum. At the same time, the 1600 cm-1 band disappears from the Raman spectra, indicating orientation of the chromophores. Cross-linking has been studied by FTIR and all-optical poling and showed an improved stability of the electro-optic thin films.
Chemistry of Materials, 1997
New and very stable polymers with good optical third-order nonlinearities have been prepared by condensation between a copolymer of maleic anhydride and octadecene and appropriate Disperse Red and Disperse Orange type chromophores. The nonlinear response of low concentration solutions of the polymers has been determined using a new numerical Z-scan technique. The polymers have been found highly stable, and their nonlinear response is very reproducible, both under intense illumination and upon several repeated experiments over months. Especially the polymer where the Disperse Orange 3 chromophore is incorporated in the main chain through imide linkages displays both the highest refractive nonlinearity and almost no two-photon absorption. Its surprisingly higher nonlinear response with respect to the parent Disperse Orange 3 is demonstrated and discussed.
Design, Methodology and Preparation of Novel Polymers for Nonlinear Optics
MRS Proceedings, 1997
One-pot post-polymerization modification reactions such as azo-coupling and tricyanovinylation reactions were employed to synthesize a series of polymers containing different nonlinear optical (NLO) chromophoric as well as ionic functionalities. We have extended and established the versatility of our earlier reported post-modification strategy to incorporate various heteroaromatic chromophores as well as ionic functionalities in the polymers, at the final stage of synthesis. The correlation between different heteroaromatic chromophore structures and the NLO properties of the polymers was extensively studied. Polymers containing heteroaromatic chromophores exhibit improved temporal stability and enhanced NLO activity. Polymers with ionic chromophores were employed to fabricate NLO active ultra-thin films using electrostatic selfassembling (ESA) technique. Attempts were also made to synthesize second order NLO active polydiacetylene derivatives using post azo-coupling reaction.
1993
The all-optical recording of a microscopic second-order nonlinear susceptibility in a new azo dye pendant polyurethane polymer is investigated. An experimental configuration which permits self-phase matched was used. The peak value of the phase-matched lightinduced second order nonlinear optical susceptibility v (2) measured at 1.06 lm reaches 62 pm/V at room temperature, which corresponds to a molecular orientation ratio of 30%. Temporal stability of the induced polar order measured by second harmonic generation revealed a reduced decay rate of the v (2) value in comparison to Disperse Red 1 pendant poly(methyl methacrylate).
Epoxy-Based Nonlinear Optical Polymers Functionalized with Tricyanovinyl Chromophores
Chemistry of Materials, 1997
Two types of new nonlinear optical polymers have been synthesized by postreaction of an epoxy-based polymer prepared from the diglycidyl ether of bisphenol A and aniline. The new polymers DGEBA-AZO-TCV and DGEBA-AN-TCV were synthesized by azo coupling of the epoxy polymer with 4-(tricyanovinyl)aniline and by reacting the epoxy polymer with tetracyanoethylene, respectively. Using an azo coupling reaction to functionalize the polymer allows introduction of the tricyanovinyl (TCV) group and extension of the conjugation length to take place in a single-step reaction. In both synthetic routes, TCV groups are introduced at the last stage of the polymer preparation, thus preventing the exposure of the TCV chromophores to harsh reaction conditions. The d 33 values for polymers DGEBA-AN-TCV and DGEBA-AZO-TCV were determined to be 27 and 66 pm/V at 1.542 µm, respectively, after corona poling. The two polymers retained 65% and 83% of the initial d 33 values after they had been heated at 80°C for 1000 h.
MRS Proceedings, 1997
A high-p 3 chromophore APII utilizing isophorone as n-conjugation bridge was processed into both PMMA guest host and crosslinked (XL) polyurethane network with various loading densities. High electro-optic coefficients, r3 3 = 30 pm/V (in PMMA) and r 33 = 32 pm/V (in polyurethane) at 1.06 pm were obtained. Alignment temporal stability ranged from 90 to 120"C for XL polymer network. There is virtually no intrinsic absorption loss at 1.3 pm (solution measurement). Also noteworthy is that high optimum loading densities of this chromophore are attainable in both cases without detectable chromophore aggregation due to intermolecular electrostatic interactions.