Michele Vacatello, Do Y. Yoon, et al.
The Journal of Chemical Physics
We present a novel method of preparing highly efficient and stable second-order nonlinear optical (NLO) polymers via chemical cross-linking induced vitrification under electric field. In this method a soluble prepolymer is first prepared that contains cross-linking sites attached to the NLO-active groups. Upon preparing samples of desired thicknesses, the prepolymer is heated (precured) to enable some chemical cross-linking and thus to increase the glass transition temperature (Tg) to an optimum for poling. The precured polymer is then heated above its Tg and subjected to a high electric field to obtain the desired alignment of NLO moieties. Subsequent chemical cross-linking (curing) under electric field continues to advance the T g and hence leads to in situ vitrification of the polymer that stabilizes the electric-field-induced orientation of the NLO moieties. Detailed results of thermal, linear optical, poling kinetics, and NLO properties are described for the polymer system prepared from tetrafunctional 4-nitro 1,2-phenylenediamine and bifunctional Bisphenol-A diglycidylether as the starting monomers. The polymer which has been cured finally at 140 °C under a very high corona field exhibits d33≅14 and d 31≅3 pm/V, determined from the Maker-fringe experiments. Most significant, however, is the fact that this polymer shows no detectable decay in second harmonic generation for over 500 h under ambient conditions and no tendency of relaxation even at 85 °C.
Michele Vacatello, Do Y. Yoon, et al.
The Journal of Chemical Physics
Manfred Eich, Ayusman Sen, et al.
Proceedings of SPIE 1989
Do Y. Yoon, Grant D. Smith, et al.
The Journal of Chemical Physics
Julius F. Remenar, Craig J. Hawker, et al.
American Chemical Society, Polymer Preprints, Division of Polymer Chemistry