New Y type chromophores were synthesized and the hyperpolarizability can be effectively translated into large electro-optic coefficients in poled polymers.

No abstract

Electro‐optic (EO) polycarbonates are prepared through copolymerization of diol nonlinear optical chromophores and bisphenol A with bisphenol A bis(chloroformate) in solution. The obtained polycarbonates exhibit good film‐forming properties and good thermal stability. The poled films of the resultant electro‐optic polycarbonates reveal the maximum EO coefficient of 75 pm/V. The obtained poled films also possess better temporal stability. These good performances endow the resultant EO polycarbonates with device application in photonics.

Dendritic julolidine-based nonlinear optical (NLO) chromophore (JTCFC) possessing isolation group was designed and synthesized to realize effective isolation of NLO chromophores in the polymer backbone.Electro-optic (EO) polycarbonates (PC-JTCFCs) consisting of the dendritic JTCFC and comonomers were prepared through a facile copolymerization strategy. The sufficiently high polymerizability of the dendritic JTCFC, which could be caused by the well-isolation of chromophores and lack of steric effect, afforded the EO polycarbonates with ultra-high molecular weight (M w up to 145 990). The DSC analysis showed that the EO polycarbonates exhibited similar T g values (near 150 C), indicating that the interchromophore interactions are effectively suppressed. The effective isolation of NLO chromophores directly suppressed the dipole-dipole interactions and improved the translation of microscopic hyperpolarizability into macroscopic EO activity. After corona poling, the synthesized EO polycarbonates exhibited a maximum EO coefficient (r 33 ) of 55 pm V À1 at 1310 nm, which was greatly enhanced as compared to the guest-host systems reported previously. Moreover, the prepared EO polycarbonates also possessed good temporal stability, 85% of the initial r 33 value of PC-JTCFC-3 could be kept after 500 h at 85 C.

Two new chromophores (A and B) were synthesized, in which a benzo [b]thiophene moiety was first introduced as a donor group. To investigate the macroscopic EO activity of the new chromophores, guest-host doped polymer films were fabricated by doping chromophores A and B into amorphous polycarbonate (APC). The poled films containing A with a loading density of 20 wt% achieved a maximum EO coefficient (r 33 ) of 42 pm V À1 at 1310 nm, while for the poled films containing B, the r 33 value is 75 pm V À1 at 1310 nm. UV-vis spectral absorption of the new chromophores were studied in solutions and films, and chromophores A and B showed a maximum absorption in chloroform of 658 nm and 688 nm, respectively. Compared to the FTC (r 33 ¼ 20-50 pm V À1 at 1310 nm, l max ¼ 685 nm in chloroform) analogues, they exhibited enhanced electro-optical activity together with a high optical gap.This new type of chromophore provided better optimization of the nonlinearity-transparency trade-off.

The electro-optic coefficient of benzo[1,2-b:4,5-b′]dithiophene unit (BDT)-based chromophores was improved to 102 pm V−1 with suitable isolation groups and electron donors.

No abstract

No abstract