Synthesis, Characterization, and Second-Order Optical Nonlinearity of a Polyurethane Structure Functionalized with a Hemicyanine Dye was written by Moon, Ki-Jeong;Shim, Hong-Ku;Lee, Kwang-Sup;Zieba, Jaroslaw;Prasad, Paras N.. And the article was included in Macromolecules in 1996.HPLC of Formula: 65350-59-6 This article mentions the following:
A new polyurethane structure with a hemicyanine dye attached to the polymer side chain was synthesized by the step growth polymerization in a reaction between (E)-N-butyl-4-[2-[4-[bis(2-hydroxyethyl)amino]ethenyl]pyridinium tetraphenylborate and 2,4-toluene diisocyanate. The mol. weight of the final product was determined to be Mn = 12,000 and Mw/Mn = 1.67. The polymer is soluble in DMF and can be processed into optical quality films by spin casting. No evidence of melting was detected by differential scanning calorimetry, suggesting that this polymer presents an amorphous phase. It shows a glass transition temperature of 121°. The macroscopic second-order hyperpolarizability χ(2) of this polyurethane was determined by measuring the second harmonic generation for a thin polymer film. The χ(2) value was in the range 1.8 × 10-7 to 5.0 × 10-7 esu, depending upon poling conditions. This high second-order activity seems to prove the earlier prediction about a possible enhancement in the nonlinear second-order properties of organic materials triggered by utilizing the strong electron-accepting nature of the pyridinium group. The alignment of the nonlinear chromophore moieties induced by elec. poling exhibits an extended temporal stability, due to the stabilizing function of the H bridges formed between the neighboring polyurethane chains, preventing the relaxation of oriented mol. dipoles. In the experiment, the researchers used many compounds, for example, 1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6HPLC of Formula: 65350-59-6).
1-Butyl-4-methylpyridin-1-ium bromide (cas: 65350-59-6) belongs to pyridine derivatives. Pyridine has a conjugated system of six π electrons that are delocalized over the ring. The molecule is planar and, thus, follows the Hückel criteria for aromatic systems. Pyridine, its benzo and pyridine-based compounds play diverse roles in organic chemistry. Pyridine-based materials are valued for their optical and physical properties as well as their medical potential. HPLC of Formula: 65350-59-6