Synthesis and characterization of accordion main-chain azo-dye polymers for second-order optical non-linearity (original) (raw)
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Nonlinear optical polymers. 1. Novel network polyurethane with azobenzene dye in the main frame
Macromolecules, 1995
Novel nonlinear optical (NLO) network polyurethane of lysine triisocyanate (LTI) with 44N-(2-hydroxyethyl)-N-methylaminol-3'-(hydroxymethyl)azobenzene (AZODIOL) dye as a NLO-phore has been prepared for second harmonic generation (SHG). A soluble prepolymer of LTI with AZODIOL was prepared, and then a thin prepolymer film was spun-cast on an indium tin oxide coated glass substrate. Two types of poling were carried out. One-step poling process: while high voltage between 5.0 and 8.0 kV was applied to the corona wire, the sample film was heated up and held at a temperature range of 70-190 "C for 10 min and then cooled down to room temperature for 40 min. Two-step poling process: while high voltage was applied to the corona wire, the sample was heated up and held at 90 "C for 1 h and then heated up again and held at a temperature range of 90-190 "C for 30 min. Then the sample was cooled down to room temperature while applying the poling field. The effects of the above poling condition and storage time and thermal annealing on SHG activity are investigated in connection with polymer structure. Better long-term thermal stability of SHG at room temperature can be obtained for the sample prepared by a two-step poling process. This better thermal stability is interpreted to be due to the smaller free volume for that sample.
Polymer Journal, 1997
New second-order nonlinear optical main-chain polymers have been synthesized in very high yields by a two-stage Knoevenagel polycondensation from 3,6-diformyl-9-heptylcarbazole and bis(cyanoacetate)s. In these main-chain polymers, two kinds of nonlinear optical (NLO) chromophores, carbazole with two acceptor groups and 4'-nitrophenylazoaniline, were introduced in a slipped shoulder-to-shoulder arrangament. All polymers were determined to be amorphous and to have glass transition temperatures in the range of 134-l 58°C by a differential scanning calorimeter. The chloroform soluble main-chain polymers show very high weight and number average molecular weights measured by a gel permeation chromatography. Thin films of the polymers could be obtained by a spin coating method. The orientation of dipoles could be achieved by applying an electric field. These poled films show good reasonable and stable second-order nonlinear optical responses.
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.
European Polymer Journal, 2015
New polymer materials with quadratic nonlinear optical (NLO) response were synthesized on the basis of bisphenol A diglycidyl ether and p-aminobenzoic acid oligomers with azochromophores in side chains. The reactive polyether polyols were obtained either in solution, or in the bulk, the latter approach being found to be preferable as it provides obtaining oligomers with rather high molecular weight and high yield. The incorporation of chromophores into the oligomers side chain was carried out by etherification reaction using two synthetic approaches: in two steps, when an aniline-containing oligomer precursor is first obtained and then used in an azo-coupling reaction, giving the desired azochromophore-containing oligomer, or in one step via a direct attachment of a hydroxyl-containing azochromophore to the reactive oligomer. The advantage of the one-stage procedure is established, since the oligomer functionalization degree with chromophore groups reached 70 mol% in this case. The synthesized oligomers are characterized by high thermal stability and heat resistance; they demonstrate good filmforming ability. NLO coefficients, d 33 , of corona-poled films of the materials based on linear oligomers and cross-linked polymers amount to $22 and 35.2 pm/V, respectively. The cross-linked materials are shown to have moderate temporal stability of the second-order nonlinear optical characteristics.
Journal of Materials Science, 1999
The second harmonic coefficient d33 values of a series of polyester nonlinear optical (NLO) polymers, differing in their electron withdrawing substituent, were experimentally measured. The observed order of contribution of the substituents towards d33 value was rationalized by a frequency factor dependence. Excellent photostability and the highest d33 value among the series have been found for the polyester with 2,4-dinitro substituents in the side chain. A possible influence of intermolecular interaction is also indicated.
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.
Synthesis and Non-Resonant Nonlinear Optical Properties of Push-Pull Side-Chain Azobenzene Polymers
Journal of Nonlinear Optical Physics & Materials, 2011
In this work we report preliminary results obtained for methacrylic polymers incorporating azobenzene side-group as nonlinear optical (NLO) active molecule. The trans-cis izomerisation properties are discussed. The third-order non-resonant nonlinear refractive index (n 2 ) and nonlinear absorption coefficient (β) are measured using the Z-scan technique at 1064 nm in the picosecond regime. The influence of different electrono-acceptor groups in azobenzene moieties on the nonlinear properties is investigated. Keywords: methacrylic monomers; azobenzene; nonlinear optical polymers; Z-scan technique to the trans-cis process accompanied by strong two-photon or saturation absorptions were observed.