Disperse Red 1 Research Articles

SELF-TRAPPING OF OPTICAL VORTEX BY USING THE MOLECULAR REORIENTATION IN PHOTOSENSITIVE POLYMERIC MATERIALS

Amorphous bulk composites were prepared by doping azo-dye Disperse Red 13 (DR13) in poly(methyl methacrylate) (PMMA) matrices. Photo-induced anisotropy of such kind of bulk polymer material was investigated experimentally by measuring the birefringence when irradiating it with linearly polarized green light. We report the first observation of self-trapping of an optical vortex based on such effect in bulk poly(methyl methacrylate) materials containing photosensitive azo-dye molecules. The dependence of the average core width of a single-charge optical vortex versus time and input power was investigated in detail.

Assessment of the sensitizing potential of textile disperse dyes and some of their metabolites by the loose-fit coculture-based sensitization assay (LCSA)

Certain textile disperse dyes are known to cause allergic reactions of the human skin. Here, we examined 8 disperse dyes and 7 products of azo-cleavage of these dyes in an in vitro assay. We used the loose-fit coculture-based sensitization assay (LCSA) of primary human keratinocytes and of allogenic dendritic cell-related cells for combined testing of the sensitizing and irritative properties of these substances. The obtained data were compared to data generated in a modified version of the local lymph node assay by our working group. Disperse Blue 1 (DB1), p-nitroaniline (pNA) and p-aminoacetanilide (AAA) showed no sensitizing potential under our experimental conditions. Disperse Blue 124 (DB124), Disperse Yellow 3 (DY3), Disperse Orange 37/76 (DO37), Disperse Blue 106 (DB106), Disperse Red 1 (DR1), 2-amino-p-cresol (ApC), Disperse Orange 3 (DO3) and 2,6-dichloro-4-nitroaniline (DCh) were categorized as extreme sensitizers. Para-phenylenediamine (pPD) was categorized as strong sensitizer, and 2-amino-5-nitrothiazole (ANT) and 2-(N-ethylanilino)-ethanol (EAE) as weak sensitizers. All dyes, except for DB1, and ApC turned out to be strong irritants. DB1, ANT and DCh showed only weak irritative potential. PPD, pNA, EAE and AAA did not show any irritative effect at the concentration range tested. These results correlate with data derived from the modified version of LLNA and human data. Therefore, the LCSA represents a suitable test system to simultaneously analyse two crucial properties of substances relevant for allergy induction.

THE INVESTIGATION OF SECOND-ORDER NONLINEAR OPTICAL PROPERTIES OF P-NITROPHENYLAZOANILINE: SECOND HARMONIC GENERATION AND AB INITIO COMPUTATIONS

p-nitrophenylazoaniline (1) belongs to the family of compounds with conjugated bonds and delocalized π-electrons, structurally similar to the well known push-pull compound Disperse Red 1 (DR1).1 Due to the assembly of the molecule, nonlinear optical (NLO) properties are expectable and can be more or less accurately predicted. To estimate the potential for second-order NLO properties, the electric dipole moment (μ), dispersion-free dipole polarizabilities (α) and first hyperpolarizabilities (β) have been determined by density functional theory (DFT) quantum chemical calculations at B3LYP/ 6-311 + G(d, p) level. According to the computation results, the synthesized compound exhibits non-zero β values and it might have second-order NLO behavior. Title compound has been synthesized and characterized by FT-IR, 1H-NMR and UV-Vis spectroscopies. The maximum one-photon absorption (OPA) wavelengths were estimated to be shorter than 450 nm by quantum mechanical computations using the configuration interaction (CI) method. The same result was achieved by UV-Vis spectra measurements, whereas the compound exhibited good optical transparency to the visible light. Quantitative measurements of second harmonic generation (SHG) at 800 nm and 1064 nm have been performed. The relative efficiency comparable with that of KDP (kalium diphosphate) has been observed with the exciting wavelength of 1064 nm, while the other wavelength led to strong absorption of produced light by the sample. In the following more detailed study on frequency-dependent first hyperpolarizabilities using time-dependent Hartree–Fock (TDHF) method have been computed at the wavelengths used in SHG measurements.

Optical property control of dye molecules using CHA and AFI nanoporous crystals

The optical properties of disperse red 1 (DR1) dye molecules can be changed by controlling the molecular configurations using AlPO4-5 (AFI) and SAPO-47 (CHA) single crystals. Polarized and temperature dependent absorption spectra show that DR1 molecules exist as cis configuration in the cages of CHA crystals. The absorption band for cis-configuration is centered at 432 nm, which does not depend on polarization angle and temperature. However, DR1 molecules are well aligned in the channels of AFI crystal with trans configuration. Its absorption band is centered at 520 nm, which shows strongly anisotropic polarizability and shifts to long wavelength with increasing temperature. It can be used as polarizer and temperature sensor. The second harmonic generation (SHG) and photoluminescence (PL) investigations show that the DR1 trans isomers in AFI matrix have potential applications in nonlinear optics.

Optical modulation of guided mode resonance in the waveguide grating structure incorporated with azo-doped-poly(methylmethacrylate) cladding layer

Optical modulation of guided mode resonance (GMR) is demonstrated in a waveguide grating structure (WGS) which contains a disperse-red1 (DR1)-doped poly(methylmethacrylate) (PMMA) cladding layer. The resonance wavelength of a GMR mode can be tuned by pumping the cladding layer with a 442 nm wavelength laser beam, because of photoinduced refractive index change in the layer. The resonance wavelength shifts to shorter wavelength side, and the shift increases with pumping power, up to a maximum shift of 5 nm. A detector was used to monitor the intensity of the light that was reflected from the WGS at the wavelengths of the GMR peak positions, and the WGS was found to exhibit optical modulation with a shortest switching time of less than 0.3s.

Self-organizing second-order nonlinear susceptibility in NLO-chromophore-doped amorphous ferroelectric poly-(cyano phenylene sulfide) polymers [Invited

We present the second order nonlinear optical properties of the Disperse Red 1 (DR1)-doped poly (cyano phenylene sulfide) (PCPS) - novel ferroelectric amorphous polymers. The PCPS possess self-organized long-range polarizations when they are annealed at temperatures higher than their glass transition point. From the unique nonelectrical poling effect, the second-order nonlinear susceptibility was obtained without the conventional poling procedures. The optimized conditions to create the second-order nonlinear optical susceptibility were also investigated in terms of the sample thicknesses and the annealing temperatures.

Polarization holographic recording in Disperse Red1 doped polyurethane polymer film

In this report holographic recording of polarisation and surface relief gratings in Disperse Red 1 (DR1) doped polyurethane polymer films was studied. In this material DR1 is chemically bounded to polyurethane polymer main chain. Polarization holographic recording was performed by two orthogonal circularly polarized 532 nm laser beams. Photoinduced birefringence is a precondition for polarization holograms recording, therefore a detailed study of a photoinduced birefringence and changes of optical properties was performed. The lasers with wavelengths of 375nm, 448nm, 532 nm and 632.8 nm were used as pumping beam for sample excitation. The photoinduced birefringence Δn was measured at 532 nm and 632.8 nm wavelengths. The photoinduced birefringence dependence on the pumping beam wavelength and intensity was investigated. Surface relief grating (SRG) formation was observed during polarization holographic recording process. A profile of SRG was studied by AFM. A relationship between SRG formation and photoinduced birefringence has been discussed.

Evidence for the applicability of a novel procedure (swelling–poling–deswelling) to produce a stable alignment of second order NLO-chromophores covalently attached to a cross-linked PMMA or polystyrene polymeric network

The “swelling–poling–deswelling” technique is a new procedure of poling crosslinked polymeric network carrying covalently attached NLO (nonlinear optical) chromophores. It is based upon a solvent-swollen crosslinked polymeric network before submission to poling. Under electrical poling, the matrix is deswelled without heating above the polymer Tg (glass transition temperature) obtaining a significant improvement of the stabilization of the alignment of the chromophores and therefore of the SHG (second harmonic generation). We determined the d 33 values of DR1 chromophore linked in different manner to PMMA (polymethylmethacrylate) and polystyrene. Crosslinked PMMA gives very good results, in fact the 40% of the d 33 value remains after 4 months respect to d 33 evaluated a couple of hours after poling. Interestingly the same stability in the time of the d 33 is observed with the crosslinked polystyrene matrix. In terms of d 33 after poling, the two systems carrying DR1 (Disperse Red 1) moieties covalently attached to the polystyrene matrix (side-chain and crosslinked) behave in a similar manner, but in terms of stability, the linear polymeric system is the best (75%), higher than all systems investigated.

Scope and limitation of the copper free thermal Huisgen cross-linking reaction to stabilize the chromophores orientation in electro-optic polymers

New methacrylate copolymers incorporating two complementary thermally cross-linkable groups (azide or ethynyl) for implementation in electro-optic devices were synthesized and their nonlinear optical properties were investigated. These copolymers were prepared from a monomer containing Disperse Red 1 (DR1) as active NLO chromophore which is end substituted either by an azide or ethynyl group connected via a rigid (phenyl) or flexible spacer (alkyl chain). The second monomer is either a trimethylsilyl-propargyl methacrylate, or an azidopropyl methacrylate or a trimethylsilyl-phenyl methacrylate. The determination of the reactivity ratios showed that the monomer containing the DR1 chromophore is more reactive than trimethylsilyl-propargyl methacrylate. The cross-linking temperatures of these polymers range from 150 °C to 187 °C depending on the rigidity of the spacers connecting the cross-linkable units. These polymers displayed relatively high macroscopic electro-optic stability, enhanced upon cross-linking by more than 40 °C relative to non-cross-linked polymers. The results underscore the importance of the flexibility of the spacers to achieve the stable bulk electro-optic response. While rigidity is favorable to maintain the orientation of the chromophores, the optimal polymer is the one containing a flexible and a rigid spacer, since the mobility of the reactive groups is a key parameter which guarantees a high cross-linking conversion within the polymer. This study demonstrates the versatility of this new cross-linking process because we showed that the reactive groups (azide or trimethylsilylacetylated groups) can be interconverted (on the chromophore or as polymer side chain) with no change on the overall electro-optic activity and its thermal stability. Furthermore, preliminary kinetic study indicates that the Huisgen reaction rate can be controlled by the substituent on the ethynyl group opening the possibility to tune the cross-linking temperature by the careful choice of this substituent.

Linear and Nonlinear Optical Properties of Disperse Red Dyes in Poly-(Cyano Phenylene Sulfide).

► Poly-(cyano phenylene sulfide) (PCPS), characterized with ferroelectric behaviors even in amorphous phase, is promising as new class of matrix polymers for nonlinear optical materials. ► Second order nonlinear optical activity from organic-dye (disperse red 1, DR1)-doped PCPS thin films, was obtained just by depositing on Au-coated thin film even without conventional poling procedure. ► A probability of charge transfer complexes between DR1 dyes and PCPS was also mentioned. Here, we report linear and nonlinear optical properties of azo dye, disperse red 1 (DR1) doped with an amorphous ferroelectric polymer, poly-(cyano phenylene sulfide) (PCPS) developed in our previous study. Our experimental results proved that the materials exhibit second-order nonlinear optical activities by depositing thin films on gold-coated substrates without conventional poling procedures. A long-range polar order for DR1 extended at least as wide as 70 nm from the Au surfaces.

Second harmonic generation in laterally azo-bridged H-shaped ferroelectric dimesogens

This contribution describes the analysis of experimental results on second harmonic generation (SHG) in a novel laterally azo-bridged H-shaped ferroelectric liquid crystal (FLC) 2, incorporating a disperse red 1 (DR-1) chromophore along the FLC polar axis, and its two mixtures with a laterally azo-bridged H-shaped FLC host 1, incorporating an azobenzene chromophore. The largest dij coefficient at the fundamental wavelength of λ = 1.6 μm is d22 = 4.5 pm/V, the coefficient along the polar axis that is optimized from the viewpoint of the chemical design of NLO FLC molecules. A linear dependence of d22 on the mole fractions of 2 in mixtures has been found, indicating that i) both 1 and 2 have a similar degree of polar order, and ii) dipole–dipole interaction in the DR-1 chromophore of 2 is not strong due to low chromophore density. This work highlights the importance of synthetic tailorability of FLC materials with extra functionality to second-order nonlinear optics applications.

Photochromic dye semi-intercalation into DNA-based polymeric matrix: Computer modeling and experiment

We use the recently formulated hypothesis of semi-intercalation of an azo-dye Disperse Red 1 (DR1) into a biopolymeric material made of deoxyribonucleic acid (DNA) complexed with the cationic surfactant hexadecyltrimethyl-ammonium chloride (CTMA) to model the unique photochromic properties of the DR1:DNA–CTMA system. Kinetic Monte Carlo simulations accurately reproduce the main experimental results of laser dynamic inscription of diffraction gratings in this photochromic material: short response time, low diffraction efficiency, single-exponential kinetics and flat wavelength dependence.

Laterally Azo-Bridged H-Shaped Ferroelectric Dimesogens for Second-Order Nonlinear Optics: Ferroelectricity and Second Harmonic Generation

Two classes of laterally azo-bridged H-shaped ferroelectric liquid crystals (FLCs), incorporating azobenzene and disperse red 1 (DR-1) chromophores along the FLC polar axes, were synthesized and characterized by polarized light microscopy, differential scanning calorimetry, 2D X-ray diffraction analysis, and electro-optical investigations. They represent the first H-shaped FLC materials exhibiting the ground-state, thermodynamically stable enantiotropic SmC* phase, i.e., ground-state ferroelectricity. Second harmonic generation measurements of one compound incorporating a DR-1 chromophore at the incident wavelength of 1064 nm give a nonlinear coefficient of d(22) = 17 pm/V, the largest nonlinear optics coefficient reported to date for calamitic FLCs. This value enables viable applications of FLCs in nonlinear optics.

Fluorescence Emission of Disperse Red 1 in PS-b-P4VP Micelles Controlled by a Toluene/Ethanol Solvent Mixture

The effects of Disperse Red 1 (DR1) in the poly(styrene-block-4-vinylpyridine) (PS-b-P4VP) micelle on micellar morphology and fluorescence emission were studied using small-angle X-ray scattering (SAXS), generalized indirect Fourier transform (GIFT), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), and photoluminescence (PL). PS-b-P4VP was coupled with DR1 in 10 mg/mL toluene/ethanol mixture solutions where ethanol and toluene were P4VP and PS selective, respectively. Hydrogen bonds were formed between the -OH group of DR1 and the pyridine ring in PS-b-P4VP. DR1 (which was coupled with P4VP) was confined in the core or corona of the micelle depending on the location of P4VP. The micellar structure was strongly dependent on varphi (weight percentage of toluene in a toluene/ethanol mixture). The PS-b-P4VP-DR1 complex in the mixture solutions showed the spherical micelle with the cores of P4VP and PS in ethanol-rich and toluene-rich solvents, respectively. The quenching phenomenon was observed for DR1 in the corona of PS-b-P4VP micelles [at varphi = 0 (ethanol)], while the fluorescence quantum yield decreased. However, significant increases in the fluorescence quantum yields at varphi = 100 were observed when DR1 was confined in the core of the PS-b-P4VP micelles. The confinement of DR1 in the hard core was more effective in fluorescence emission than that in the soft corona due to the slow trans-to-cis transition of DR1.

Preparation and optical properties of sol–gel derived organic–inorganic hybrid waveguide films doped with disperse red 1 azoaromatic chromophores

We report here on TiO 2/organically modified silane (ormosil) organic–inorganic hybrid waveguide films doped with disperse red 1 (DR1) azoaromatic chromophores and derived by a low-temperature sol–gel process for photonic applications. Acid-catalyzed solutions of γ-glycidoxypropyltrimethoxysilane and methyltrimethoxysilane mixed with tetrabutyl titanate are used as matrix precursor for the hybrid films. Third-order nonlinear and photo-responsive properties of the hybrid films are studied by using a z-scan technique and a UV–vis absorption spectroscopy. Results indicate that the hybrid films have a large third-order nonlinear susceptibility and an obvious trans-to-cis photoisomerization under UV light irradiation. The planar waveguide and structural properties of the hybrid films are also characterized by a prism coupling technique, thermal gravimetric analysis, and Fourier-transform infrared spectroscopy. These results indicate that the as-prepared hybrid films are promising candidates for integrated optics and photonic applications, which allow directly integrating on the same chip waveguide devices with the functionalized devices.

Fabrication of a Plastic Optical Fiber (POF) by Using Direct Core Solution Injection (DCSI)

We have fabricated a nonlinear plastic optical ber (POF). Direct core solution injection (DCSI) into the hole of a cladding preform formed by polymerization of the cladding solution was proposed for making the nonlinear POF. The preform of the ber was pulled into the ber following polymerization of core solution. The cladding solution was made of methyl methacrylate (MMA), benzyl-Butyl Phthalate (BBP) and benzoyl Peroxide (BPO). Disperse red 1 (DR1) was added to the core solution to control the refractive index. The transmission characteristics of the fabricated POF and the temperature dependence of the loss were investigated. The thermo-optic coe cient of the POF was {0.0002/ C.

Covalent attachment of chromophores to chlorinated copolymers for optical waveguides: Synthesis and optical characterization

Polymeric optical devices are attracting increasing interest in the field of photonics because of the very appealing performances as structures for both propagating and modulating light signals according to the properties of the employed organic materials. This paper reports the preparation and characterization of low-loss polymer waveguides fabricated from chlorinated copolymers by photochemical crosslinking. A novel monomer derived from reaction between glycidyl methacrylate (GMA) and the chromophore Disperse Red 19 (DR19) was prepared and successfully copolymerized with GMA and chlorostyrene (CS) to obtain the dye-modified copolymer. The latter was crosslinked by photoinitiated polymerization of the pendant epoxy groups, to obtain stable polymeric waveguides. It was found that the major product of the reaction between GMA and DR19 was formed through transesterification of the methacrylate with elimination of glycidol, while traces of products deriving from the epoxy ring-opening reaction were detected. The presence of the nitro substituent on DR19 favoured chain-transfer reactions during the polymerization reaction, leading to a decrease in the polymerization degree. It was also observed that the presence of grafted DR19 negatively affected the crosslinking reaction, as a lower epoxy group conversion was observed for the modified copolymer. Thermal analysis showed increased thermal stability for the copolymer containing DR19. m-line spectroscopy was used to measure the refractive index at 632.8nm. The experimental results confirm that the new class of chlorine-based polymeric materials represent a very attractive proposal in the panorama of materials employed in the fabrication of electro-optical devices for telecommunication applications.

High Cost Performance Organic–Inorganic Hybrid Material for Electro-optic Devices

We report a low-cost electro-optic (EO) sol-gel material with large EO coefficient and excellent poling stability for EO devices. Disperse red 1 (DR1) chromophore is doped in the three-dimensional silicon dioxide/titanium dioxide network possessing a high γ33 (88 pm/V at 1300nm wavelength and 71 pm/V at 1550 nm wavelength). Favourable poled stability (less than 5% relaxed after 2500 hours at 80°C) and low absorption are demonstrated. Strip-loaded waveguide Mach–Zehnder (M-Z) modulators are implemented based on this synthesized EO material, showing 7 V half-wave voltage and less than 9 dB insertion loss at 1550 nm wavelength.

Photoinduced Birefringence in Nanostructured SiO2:DR1 Sol–Gel Films

Pump-probe photoinduced birefringence measurements were carried out in amorphous and in nanostructured sol-gel films with Disperse Red 1 (DR1) azochromophores embedded in a SiO2 matrix. X-ray diffraction (XRD) patterns determine the long-range nanostructure order of the films, exhibiting a lamellar nanostructure, with two different d-spacings, due to the presence during the sol-gel process of the Sodium Dodecyl Sulfate (SDS) or of the Cetyltrimethylammonium Bromide (CTAB) ionic surfactants. The photoinduced birefringence measurements were performed on fresh and on heat treated films as a function of the pumping time. The measurements give us information about the effect of the nanostructures on the azochromophores orientation dynamics. As a result, for the same azochromophores concentration, annealed nanostructured films exhibited the largest azochromophore mobilities but by the other side, amorphous films had the largest signal intensities. Besides, we established a phenomenological model for the analysis of the azochromophores orientation in the films as a function of the pumping time.

Growth of thin polymer films containing side-chain azo-dye analyzed by atomic force microscopy

Thin films containing both the azo-dye disperse red 1 (DR1) and the poly(methylmetacrylate) (PMMA) or the poly(phenylenevinylene) (PPV) are deposited by Langmuir–Blodgett and spin coating techniques on various substrates. The morphology, surface structure and growth pattern of the azo-dye-polymers were studied by atomic force microscopy. Nucleation and growth processes are responsible for the generation of different structures. The spin coated films were additionally oriented using the electric field poling method (corona poling). The film homogeneity is improved by this method in all cases. Due to the polar character of DR1 molecules, rod-like sub-structures are observed after the corona poling process in DR1–MMA films. The indium tin oxide surface enhances reorientation of the azo-dye-polymer molecules during corona poling and results in a significant reduction of the surface roughness.