Synthesis and nonlinear optical properties of novel Y‐type polyurethane containing tricyanovinylthiazole with enhanced thermal stability of second harmonic generation

Abstract

A novel Y-type poly [iminocarbonyloxyethyl-5-methyl-4-{2-thiazolylazo-4-(1,2,2-tricyanovinyl)}resorcinoxyethyloxycarbonylimino-(3,3 0 -dimethoxy-4,4 0 -biphenylene)] 4 containing 5methyl-4-{5-(1,2,2-tricyanovinyl)-2-thiazolylazo}resorcinoxy groups as nonlinear optical (NLO) chromophores, which constitute part of the polymer backbone, was prepared and characterized. Polyurethane 4 is soluble in common organic solvents such as acetone and N,N-dimethylformamide. It showed a thermal stability up to 250 C in thermogravimetric analysis thermogram and the glass-transition temperature (T g ) obtained from differential scanning calorimetry thermogram was around 118 C. The second harmonic generation coefficient (d 33 ) of poled polymer films at 1560 nm fundamental wavelength was around 8.43 Â 10 À9 esu. The dipole alignment exhibited a thermal stability even at 12 C higher than T g , and there was no SHG decay below 130 C due to the partial main-chain character of the polymer structure, which is acceptable for NLO device applications.

Facile synthesis and electro‐optic activities of new polycarbonates containing tricyanofuran‐based nonlinear optical chromophores

“…Before poling, the films appeared very flat and clean. After poling, however, the films were changed, and numerous hills and valleys appeared on the poled films, which could be seemed as the evidence of the chromophores alignment during the poling process . The AFM images further indicate that the synthesized EO polycarbonates have excellent film‐forming properties, it also demonstrated that the materials have excellent dielectric strength because good film quality was retained after high electric field poling according to the AFM scans of the poled films.…”

“…Atomic force microscope (AFM) is usually used to investigate the surface morphology of polymer films. It could reveal the domain structures of NLO chromophores, the film‐forming properties, and the differences of the films morphology before and after poling . Figure shows the AFM scans of the spin‐coated films of PC‐TCFC‐2 and PC‐DFTC‐3 before and after poling.…”

“…The structures of the resulting polycarbonates were confirmed by 1 H‐NMR and Fourier transform infrared (FTIR). Like some other such Y‐type EO polymers reported, the resultant Y‐type EO polycarbonates possess both the merits of main‐chain and side‐chain EO polymers, such as good solubility and stable dipole alignment. These new polycarbonates also exhibit good film‐forming property and high thermal stability.…”

Synthesis of cross-linked polyurethane elastomers with the inclusion of polar-aromatic moieties (BA, PNBA and 3, 5-DNBA): Electrical and thermo-mechanical properties analysis

“…More recently, Petroff et al used the same strategy and created polar molecules doped polydimethylsiloxane (PDMS) foams and measured the electrical and mechanical properties and by tuning these properties they achieved a maximum d 33 piezo-coefficients about 153 pCN −1 [4]. Furthermore, many researchers showed that the inclusion of polar molecules in polyurethane can create either high piezoelectricity or NLO materials [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. We motivated by reviewing the previous works to do further experiments to observe the effect of polar moieties on other properties of polyurethane.…”

Synthesis and nonlinear optical properties of novel Y-type polyurethane containing nitrothiazolylazoresorcinoxy groups with highly enhanced thermal stability of second harmonic generation

“…Physically crosslinked systems via hydrogen bonds have advantages such as homogeneity and good processability relative to chemically crosslinked systems, which suffer from significant optical loss and poor solubility. Recently we prepared novel polyurethanes containing tricyanovinylthienylresorcinol, tricyanovinylthienylcatechol, tricyanovinythiazolylazoresorcinol and nitrophenylazoresorcinol as NLO chromophores. The resulting polymers exhibit enhanced thermal stability of second harmonic generation (SHG), which stems from the stabilization of the dipole alignment of the NLO chromophores at high temperature.…”