Characterization of the linear and nonlinear optical properties of polydiacetylenes

The withdrawal technique is used to obtain the 9-BCMU polydiacetylene (PDA) in the red and blue phases. The ordered blue phase film has an exciton band edge which is shifted by 0.3 eV from that in the less ordered red phase film. The chiral 3-SMBU PDA is found to only exist in an amorphous form in the solid state and films of this polymer are obtained by casting onto a glass substrate. Its absorption edge is intermediate between those obtained in the 9-BCMU films. Refractive indices of 1.65 +/- 0.01 are obtained at 632.8 nm and 1.57 +/- 0.01 at 1.3 micrometers in the red phase 9-BCMU film using a prism coupling technique.