Investigation of orientational dynamics in poled nonlinear optical polymers by secondary poling

The orientational motion of molecules in a nonlinear optical polymer was studied by secondary poling at a temperature below the glass transition temperature (Tg), after initial poling at above Tg. It was found that the molecules showed asymmetric orientational response for secondary poling between directions along and opposite to the initial poling direction. The result suggests that at sub- Tg temperatures, the local environment of the molecules becomes asymmetrical after the initial above- Tg poling, in a way that is contrary to expectation. © 2005 American Institute of Physics.