A new class of IPN system has been prepared and investigated. This IPN system combines the polybismaleinimide network and the NLO-active phenoxysilicon network. The second-order NLO coefficients, d33, values of the samples range from 2.5 to 6.7 pm/V depending on the composition and the processing conditions. The temporal stability of the second-order nonlinearities for these samples at 110 deg C varies from 47 to 88% retention after 274 h.
Poled polymers doped with nonlinear optically active chromophores combine the large second order nonlinearity of the dopant dye molecules with the optical quality of the polymer. The material design flexibility afforded to doped polymers makes them attractive in a large variety of devices and applications. This book addresses the critical science and technology issues in the development and application of poled polymers, with an emphasis on the stabilization of poled polymers and their special applications to second harmonic generation (SHG) and electro-optic (EO) devices.
Polymeric materials with second order nonlinear optical (NLO) properties are of much interest for applications such as waveguide electrooptic modulation and frequency doubling devices. These NLO properties are presented when the chromophores are aligned in a noncentrosymmetric manner. The alignment of NLO chromophores in the poled polymers must be sufficiently stable at temperatures above 100 deg C in order to use them in practical devices. Several approaches have been adopted to enhance the temporal stability of the poled polymers. Enhanced temporal stability of second order NLO properties in several poled polymer systems has been achieved by crosslinking reactions. The resulting crosslinked network has a higher glass transition temperature and a denser matrix which prevent the aligned NLO chromophores from relaxing to a random orientation. However, slow decay of second order NLO properties at elevated temperatures was still observed in the polymers. Furthermore, the general form of the relaxation curves for the crosslinking polymers do not appear to be distinctly different from those for the guest/host systems. We have selected an interpenetrating polymer network (IPN) containing aligned NLO chromophores to test these issues. An IPN is a structure in which two or more networks are physically combined. The IPN is known to be able to remarkably suppress the creep and flow phenomena in polymers. Permanent entanglement of the two polymer chains restrict their mobility which leads to a significantly more stable NLO material. In this paper, we report on the design, synthesis and characterization of an NLO active IPN ... Interpenetrating polymer network, Nonlinear optical polymer.
Presents the most recent developments in second-order nonlinear optical polymers. Covers the most important technologies necessary to achieve commercially viable devices based on special polymeric materials with second-order nonlinear optical properties. Discusses important molecular design considerations, how to process the polymers into films, the stability of the films, their optical properties, and prototype devices that can be made from these films.
Nonlinear optical (NLO) polymers have shown increased potential in practical applications, such as frequency doubling and electro-optic modulation, due to their large nonlinearity and ease of processing. A practical NLO polymer will need to possess large second-order nonlinearity, excellent temporal stability at elevated temperatures, and low optical loss. 1 A number of NLO polymers have been developed to exhibit large second-order NLO coefficients comparable to those of the inorganic NLO materials which are currently in use in devices. 2,3 However, the major drawback of NLO polymers is the decay of their electric field induced second-order optical nonlinearities. This decay is a result of the relaxation of the NLO chromophores from the induced noncentrosymmetric alignment to a random configuration. Numerous efforts have been made to minimize this decay through different approaches. 4 Recently, we have reported on an approach to stable second-order NLO polymers using an interpenetrating polymer network (IPN) structure. 5,6 This IPN system, with the hybrid properties of a high glass transition temperature (Tg), an extensively crosslinked network, and permanent entanglements, exhibited excellent temporal stability at elevated temperatures. 6 In this report, a new IPN system, modified from the one reported earlier,5 with higher degree of crosslinking density and larger NLO chromophore density is investigated. Electro-optic modulation, Interpenetrating polymer network, Second-order nonlinearity, Optical loss.
This book explores functional polymers containing aromatic azo chromophores in side-chain, main-chain and other parts of their structures, known as azo polymers and which share common photoresponsive properties. It focuses on the molecular architecture of azo polymers, the synthetic methods and their most important functions, such as photoinduced birefringence and dichroism, surface-relief-grating (SRG) formation, and light-driven deformation of liquid crystal elastomers. It combines a general survey of the subject and in-depth discussions of each topic, including numerous illustrations, figures, and photographs. Offering a balance between an introduction to the core concepts and a snapshot of hot and emerging topics, it is of interest to graduate students and researchers working in this and related fields. Xiaogong Wang is a Professor at the Department of Chemical Engineering, Tsinghua University, China.
The linear optical and second order nonlinear optical (NLO) properties of an interpenetrating polymer network (IPN) have been investigated. For the poled and cured IPN samples, large second order NLO coefficients, d33, were measured at 1.064 um and 1.542 um. The linear electrooptic coefficients, r33, were determined at various wavelengths. The poled and cured IPN samples showed no measurable decay of the second-order optical nonlinearity after being treated at 110 deg C for more than 1000 hours. This excellent long-term stability of the NLO property is ascribed to the novel interpenetrating crosslinked molecular structure of the IPN system.
