Premium
Synthesis and optical properties of polyurethanes containing a highly NLO active chromophore
Author(s) -
Woo Han Young,
Shim HongKu,
Lee KwangSup
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980701)199:7<1427::aid-macp1427>3.0.co;2-q
Subject(s) - chromophore , polymer chemistry , polymer science , materials science , photochemistry , chemistry
Two types of new polyurethanes with a highly NLO active chromophore, 2‐[4‐[4‐[bis(2‐hydroxyethyl)amino]phenylazo]benzylidene]malonitrile (HAPM), in the polymer side chain were synthesized (PU1‐DCN and PU2‐DCN) and characterized. The diisocyanate components of the polymers are 2,4‐tolylene diisocyanate and 3,3′‐dimethoxybiphenyl‐4,4′‐ylene diisocyanate. The molecular weights of PU1‐DCN and PU2‐DCN were determined to be M̄ w = 23000 ( M̄ w / M̄ n = 2.19) and M̄ w = 22000 ( M̄ w / M̄ n = 2.34), respectively. The final products are readily soluble in polar aprotic organic solvents, like tetrahydrofuran, N,N ‐dimethylformamide, cyclohexanone, etc. Good optical quality films were obtained by spin coating. The glass transition temperatures of both polymers were found to be 158–159°C. They showed no melting points in the DSC curves, suggesting an amorphous phase. It was found that the electro‐optic coefficient of PU1‐DCN was r 33 = 62.7 pm · V −1 at 633 nm wavelength. The macroscopic second‐order hyperpolarizability at 1064 nm wavelength was determined to be χ (2) = 136 pm · V −1 for PU1‐DCN and χ (2) = 120 pm · V −1 for PU2‐DCN.