Investigation of third-order nonlinear optical susceptibility in polymer complexes of diarylidenealkanones

The third-order nonlinear optical susceptibility in polymer complexes of diarylidenealkanones has been investigated by the third harmonic generation technique at a wavelength of 1.06 μm. The macroscopic nonlinear susceptibility χ ⁽³⁾ measured is compared with the calculated γ values of the second-rank molar hyperpolarizability tensor. It is demonstrated that low-molecular chromophores can be used in syntheses of the stable polymer composite systems with a high nonlinear optical susceptibility. A further improvement in the nonlinear optical properties of complexes between deprotonated chromophores and high-basicity polymers can be achieved using the proposed methods. __________ Translated from Fizika Tverdogo Tela, Vol. 42, No. 11, 2000, pp. 2099–2102. Original Russian Text Copyright ? 2000 by Ten’kovtsev, Yakimanski, Lukoshkin, Dudkina, Boehme.     

Synthesis and properties of glycidyl methacrylate copolymers with side chromophore groups

A number of styrylquinoline chromophores with carboxyl groups have been prepared through the interaction of 2-methylcinchonic acid with aromatic aldehydes of various chemical structures. The copolymer of glycidyl methacrylate and methyl methacrylate carrying side epoxide groups has been synthesized, and the chemical modification of the copolymer with the above chromophores has been performed. The thermal, spectral, and nonlinear optical properties of the chromophores and modified polymers have been studied.     

Influence of the Chemical Structure of Diarylpenta-1,4-dien-3-one Chromophores on the Nonlinear Optical Properties of Their Polymeric Complexes with Poly-1,10-decamethyleneacetamidine

A study was made of the ability of the ionic complexes formed by diarylalkadienone chromophores with poly-1,10-decamethyleneacetamidine to exhibit third-order nonlinear-optical effects. The chemical structure of the chromophores was correlated with the third harmonic generation efficiency.     

Nonlinear optical properties of thermally stable silicon-containing poly(o-hydroxyamide) with a covalently bound chromophore in a side chain

The time dependence of the nonlinear optical properties of the films prepared from silicon-containing poly(o-hydroxyamide) with a covalently bound 4-nitroazobenzene-based chromophore in a side chain is investigated in isothermal and thermally stimulated modes. It is revealed that, when the onium salt, i.e., triphenylsulfonium hexafluorophosphate, is added to a polymer solution, the second harmonic generation signal is characterized by an unusual time dependence. The assumption is made that the introduction of the onium salt favors the formation of the benzoxazole structure during the process of polarization (poling). This structure facilitates the orientation of nonlinear optical fragments and, hence, leads to an improvement of the nonlinear optical properties of the polymer film.     

Polyamidoimides with side chromophoric groups

A new method was elaborated for the introduction of chromophores into the side chains of polymers by esterification of polyamidoimides containing side carboxy groups with glycidyl ethers of dyes, 4-(4-nitrophenylazo)phenol and 4-(6-nitrobenzothiazol-2-ylazo)phenol. The optimum modification conditions were found that made it possible to esterify 15, 30, 50, and 90% of the carboxy groups. The synthesized polymers possess valuable physicomechanical properties (E = 2.8–3.3 GPa, σ_u = 69–90 MPa, ε_u = 38–77%) and glass transition temperatures of 115–125 °C, depending on the degree of esterification. After chromophore orientation in the corona discharge, all the polymers demonstrate nonlinear optical properties of the second order. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1438–1444, June, 2005.     

Influence of Metal Complexing on the Nonlinear-Optical Properties of Compounds with High Molecular Symmetry

Coordination bonding of 1,5-diphenylpentadienone was studied with the aim to prepare compounds exhibiting third-order nonlinear optical properties. The volume resistivity of these compounds was studied as influenced by the third-order nonlinear susceptibility tensor.     

Effect of the aggregation of 4-[5-(4-hydroxyphenyl)-3-oxopenta-1,4-dienyl]benzoic acid and its potassium salt in a polymeric matrix on the third-order nonlinear optical susceptibility of polymer-chromophore composites

Aggregation of 4-[5-(4-hydroxyphenyl)-3-oxopenta-1,4-dienyl]benzoic acid (chromophore) and its potassium salt in optically neutral polymeric matrices was studied. The dependence of the third-order nonlinear optical properties of the chromophore-polymer composites on the aggregate size was determined.     

Nature of the nonlinear second-order optical susceptibility in molecular materials with C 2v molecular symmetry

The method of second-harmonic generation at the wavelength 1.06 μm is used to study the nonlinear second-order optical susceptibility of polycrystalline molecular materials with C _2v molecular symmetry belonging to the group of 2,6-dibenzadiene substituted cyclohexanes. The magnitude of the second harmonic signal is comparable to or greater than its value for polycrystalline urea and depends on the type of substituent (the stronger the donor properties of the substituent, the stronger the signal). It is shown that in the majority of the compounds investigated the large nonlinear optical polarizability observed is associated with the octupole moment of the molecule. Fiz. Tverd. Tela (St. Petersburg) 39, 1687–1689 (September 1997)     

Structure, phase (aggregate) state, and optical properties of a new heat-resistant polymer with a nonlinear optical chromophore

A new heat-resistant copolymer (II) with a nonlinear optical chromophore in a side chain was synthesized by the etherification of side hydroxyl groups in chains of silicon-containing poly(o-hydroxyamide) (I) with 4′-{(6-chlorohexyl)methylamino}-4-nitroazobenzene (chromophore) under conditions of phase-transfer catalysis. The structure and phase (aggregate) states of copolymer II were investigated using x-ray diffraction and differential scanning calorimetry. It was shown that the substitution of chromophore molecules for up to 15% of hydrogen atoms in hydroxyl groups of amorphous copolymer I most likely leads to an independent arrangement of the chromophoric groups and the formation of crystal domains. It was established that this ordering substantially affects the stability and efficiency of the nonlinear optical properties of films prepared from copolymer II and is probably responsible for the slow decay of the second-harmonic generation signal in the sample.     

Nonlinear optical properties of polyamidine complexes of a series of modified oligomeric ω,ω′-diaminopropylene oxides

The third-order nonlinear optical susceptibility χ⁽³⁾ in poly(octamethylene acetamidine) complexes of a series of modified oligomeric ω,ω′-diaminopropylene oxides is investigated by the third-harmonic generation technique at a wavelength of 1064 nm. It is demonstrated using UV spectroscopy that the interaction of the aforementioned chromophore-terminated polymers with polyamidine leads to the formation of network structures in which the polymer network is formed as a result of the ionic interaction. The ionic intermolecular complexes formed in this case are capable of generating the third harmonic. An increase in the length of the polymer chain in the series of modified ω,ω′-diaminopropylene oxides leads to a decrease in the absorption coefficient of the chromophore fragment and a considerable decrease in the nonlinear optical response χ⁽³⁾