Third-order nonlinear optical interaction and conformational transition in poly-4-BCMU polydiacetylene studied by picosecond and subpicosecond degenerate four wave mixing

Abstract
The electronic third-order nonlinear optical interaction in a solution cast film of a polydiacetylene has been studied by degenerate four wave mixing. The results demonstrate a subpicosecond response and a very high χ(3) value. The χ(3) value changes considerably during the thermally induced conformational transition in the film in which the effective π-electron conjugation is reduced.