Side-chain Nonlinear Optical Polymer Research Articles

Polymer-Based Devices for Optical Communications

Polymers are emerging as new alternative materials for optical communication devices. We developed two types of polymer-based devices for optical communications. One type is for ultra high-speed signal processing that uses nonlinear optical (NLO) polymers in such devices as electro -optic (EO) Mach-Zëhnder (MZ) modulators and EO 2×2 switches. The other is for WDM optical communications that use low-loss optical polymers in such devices as 1×2, 2×2, 4-arrayed 2×2 digital optical switches (DOSs) and 16×16 arrayed waveguide grating (AWG) routers. For these devices, we synthesized a polyetherimide-disperse red 1 (PEI-DR1) side chain NLO polymer and a low-loss optical polymer known as fluorinated polyaryleneethers (FPAE). This paper presents the details of our development of these polymeric photonic devices considering all aspects from materials to packaging.

Effect of pressure and temperature on chromophore reorientation in a side-chain nonlinear optical polymer

Second harmonic generation (SHG) was used to measure the temperature dependence of the reorientation activation volume of the side-chain copolymer poly(disperse red 1 methacrylate-co-methyl methacrylate) (DR1-MMA). The decay of the SHG signal from poled films of DR1-MMA was recorded at hydrostatic pressures up to 3060 atm and at different temperatures between 25°C below the glass transition temperature (Tg) to 35°C above it. The activation volume, ΔV*, decreased with increasing temperature. The data suggests that the coupling between chromophore reorientation and the long-range motion of the polymer is stronger for the DR1-MMA side-chain system than in previously measured guest–host systems. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 2793–2803, 1998

Temperature-domain analysis of primary and secondary dielectric relaxation phenomena in a nonlinear optical side-chain polymer

The investigation of dipole relaxation processes in nonlinear optical (NLO) polymers containing chromophore dipoles with large hyperpolarizabilities is important for optimizing the poling process and for predicting the long-term stability of the poling-induced order. The primary or α relaxation is difficult to assess by dielectric spectroscopy in polymers with high glass transition temperature due to thermally induced chromophore degradation. A fast experimental procedure is developed for the investigation of dielectric relaxation processes in NLO polymers, without severely inducing chromophore degradation. The procedure is based on the measurement of the dielectric function ε̃(T)=ε′(T)−iε″(T) at a few frequencies from 30 Hz to 30 kHz, while heating the polymer at a constant rate. The complex plane representation of the temperature-dependent dielectric function is used to determine the distribution of relaxation times, while the temperature-dependent mean relaxation time τα(t) is numerically determined from the dielectric loss ε″(T). With only three decades in frequency, information on five decades in time or 90 K in temperature is gained above the glass transition temperature. The strong α and the weak β relaxation below the glass transition are separately investigated by thermally stimulated depolarization after a suitable two-step poling procedure. The method has been applied to a typical polyimidelike side-chain nonlinear optical polymer with modified Disperse Red 1 chromophores. Even below room temperature, a γ-relaxation process is observed, demonstrating significant mobility of the chromophores much below the glass transition. From the results of thermally stimulated depolarization it is concluded that the initial fast decay of the electro-optical response to a temporally stable value is related to the partial depolarization caused by the β relaxation.

Long term stability of a poled side-chain nonlinear optical polymer

A side-chain nonlinear optical polymer consisting of copolymers of 4-methylamino-4′-nitrostilbene and methacrylate was poled and shown to be orientationally stable for almost 8 yrs. At approximately 110 °C below its glass transition, its electrooptic coefficient was reduced by less than 25% of its initial value. In addition, adding an annealing step during the poling process further improved its orientational stability. These behaviors are consistent with existing empirical models describing poling relaxation of nonlinear optical polymers, and demonstrate that with appropriate molecular design, they can become viable nonlinear optical materials for commercial devices.

Investigation of Dipolar Relaxation Processes in a Side-Chain Nonlinear Optical Polymer

AbstractAmorphous thin films of a typical side-chain nonlinear optical polymer were investigated by means of dielectric spectroscopy and thermally stimulated depolarization current (TSDC) within the temperature range -40°C to 230°C. Three distinct relaxation processes, labelled α, β and γ were observed. The α-relaxation, associated with the glass transition, is well described by the Vogel-Fulcher relation, while the sub glass transition β and γ-relaxation follow Arrhenius relations. The advantage of TSDC over dielectric spectroscopy is demonstrated for the investigation of the weak β-relaxation in the side-chain polymer. Furthermore, the β -relaxation is responsible for the initial, fast decay of the electro-optical response of the side-chain polymer at room temperature.

Organic Nonlinear Optical (NLO) Polymers. A Study of in-Situ Poling and Quaternization/Crosslinking of Polymers by a NLO-Tweezer

The paper describes the syntheses of a NLO-tweezer, α,α'-bis[N-ethyl-N-(4'-stilbazolyl)-amino]-m-xylene (3), functionalized copolymers 4a [poly(2-bromoethyl methacrylate)/polystyrene], 4b [poly(2-chloroethyl methacrylate)/polystyrene], and 4c [poly(3-chloropropyl methacrylate)/polystyrene], and NLO-phore 6, 4'-(N-ethyl-N-hexylamino)stilbazole. Kinetic analyses were carried out for the cross-linking/quaternization reaction of the NLO-tweezer with copolymers 4a, 4b, and 4c. Energy of activation (E a ) values of 15.3, 18.8, and 18.4 kcal/mol, respectively, were experimentally determined. Films containing 9.1 wt % of the NLO-tweezer and NLO-phore 6 were subjected to corona poling with heating (90-120 °C) for varying lengths of time. The materials displayed improved temporal stability for the second harmonic (SH) signal with an increasing degree of quaternization, and the best temporal stability (at 80 °C) for the SH signal was observed for the side-chain NLO polymer (i.e. from NLO-phore 6), which was not cross-linked. The NLO-tweezer, which did form a cross-linked material, showed an initial rapid loss of SH signal ; however, the long term signal decay was similar to the side-chain analog.

Second-Order Optical Nonlinearities in Perfluoroalkylsulfonyl Substituted Azo Dyes

Abstract The second-order nonlinear optical coefficients d33 (-2ω:ω, ω) of polymer films doped with novel azo dyes, which have a perfluoroalkylsulfonyl group as an electron acceptor and an extended π-electron conjugated system, are determined by second-harmonic generation (SHG) measurements. Thin polycarbonate (PC) film doped with 4-(4-(4-perfluorobutylsulfonylphenylazo) naphthylazo)-N-ethyl-N-hydroxyethylaniline showed a large d33 value, 67 pm/V, at a wavelength of 1064 nm. The decay of the d33 values was slow due to the stability of the molecular arrangement in a polymer matrix at high temperature. In addition, a side-chain nonlinear optical polymer with this novel disazo dye is synthesized and the decay of d33 values is estimated.

Synthesis and Characterization of Novel Side-Chain Nonlinear Optical Polymers Based on Poly(1,6-heptadiyne) Derivatives

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and Characterization of Novel Side-Chain Nonlinear Optical Polymers Based on Poly(1,6-heptadiyne) DerivativesHyung-Jong Lee, Su-Jin Kang, Kwan Kyu Kim, Hyun-Nam Cho, Joon-Taik Park, and Sam-Kwon ChoiCite this: Macromolecules 1995, 28, 13, 4638–4643Publication Date (Print):June 1, 1995Publication History Published online1 May 2002Published inissue 1 June 1995https://doi.org/10.1021/ma00117a039RIGHTS & PERMISSIONSArticle Views105Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (807 KB) Get e-Alerts Get e-Alerts

Synthesis of new donor-acceptor diarylacetylene chromophores and preparation of corresponding nonlinear optical side-chain polymers

New donor-acceptor substituted diarylacetylene hyperpolarizable chromophores bearing an amino group as donor and a methylsulfonyl group as acceptor at each extremities of an azatolane conjugated path have been designed to get a good nonlinearity-transparency trade-off, and synthesized. Corresponding methacrylate esters have been obtained then submitted to free radical polymerization, leading to novel side-chain nonlinear optical polymers and copolymers.

Improving the thermal stability by anchoring both ends of chromophores in the side-chain nonlinear optical polymers

We report our study of a new side-chain second-order nonlinear optical polymer in which both ends of the chromophores are anchored by thermal crosslinking during electric field poling. A sizable second-harmonic generation coefficient d33 of 60 pm/V was measured at 1064 nm fundamental wavelength with corona poling. After anchoring both ends of the chromophores, the thermal stability of the poling alignment was greatly improved and the nonlinear optical properties were shown to be stable at both 90 and 125 °C. Channel waveguides were defined in the polymer thin films by reactive ion etching.