Influence of gamma radiation on the electrooptic behavior of planar nematic liquid crystal cells

We irradiated planar nematic liquid crystal cells with gamma-rays, to study the radiation hardness of their electrooptic characteristics. From the evolution of the electrooptic retardance curve with irradiation dose, we estimated the change of the characteristic liquid crystal material parameters with dose, using a nonlinear least square fitting algorithm. The overall gamma radiation hardness of the device is satisfactory up to doses of 456 kGy (H/sub 2/O). Two effects, however, influence the operation of liquid crystal cells as voltage tunable retarders. Radiation affects first the cohesion of the liquid crystal molecules at the boundaries and second, the conductivity of the liquid crystal cells.