Main-chain accordion polymers for nonlinear optics

Synthesis and Characterization of Poly(pyridinium triflate)s with Alkyl and Aromatic Spacer Groups for Potential Use as Nonlinear Optic Materials

A series of poly(pyridinium triflate)s with alkyl and aromatic spacer groups were prepared by ring transformation polymerizations between various pyrylium triflates and diamines. The polymers are soluble in polar aprotic solvents and form tough, clear, flexible films. These novel polymers were characterized by IR, NMR, UV, DSC, TMA, and TGA. The polymers were thermally stable to 340 °C under nitrogen, and had softening points that ranged from 151 to 255 °C. Thin films were shown to display electrostrictive behavior in the presence of an applied electric field, with the amount of transverse strain being proportional to the concentration of charge in the polymer.

Dendronlike main-chain nonlinear optical (NLO) polyurethanes constructed from "H"-type chromophores: synthesis and NLO properties

For the first time, a series of dendronlike main-chain polyurethanes have been successfully designed and synthesized, in which different isolation groups with different sizes were introduced to modify the subtle structure of the used "H"-type chromophores, according the concept of "suitable isolation groups". Thanks to the advantages of "H"-type chromophores and the introduced suitable isolation group, all of the polymers demonstrated large NLO effects, good processability, improved optical transparency, and thermal stability. The obtained experimental results indicated that the utilization of "H"-type chromophores might be a promising choice to efficiently translate the large beta values of the organic chromophores into high macroscopic NLO activities of polymers.

From Controllable Attached Isolation Moieties to Possibly Highly Efficient Nonlinear Optical Main-Chain Polyurethanes Containing Indole-Based Chromophores

For the first time, the indole-based NLO chromophores were embedded into the polymer main chain, and different isolation groups were attached to their donor side with the efforts of adjusting the NLO properties of the resultant main-chain polyurethanes, according to the site isolation principle. Thanks to the main-chain structure and the advantages of the indole-based chromophores, all the polymers show excellent transparency, good processability, thermal stability, and relatively good NLO effects. The tested NLO properties of the polymers demonstrate that there is a suitable isolation group present for the sulfonyl-based chromophore to boost its microscopic beta value to a possibly higher macroscopic NLO property efficiently.