A Driven Voltage-Controlled Reversible Electrooptic Effect in a Smectic A Phase II. PVA Anchoring

The driven voltage-controlled reversible electrooptic effect in a smectic A phase with a preceding nematic phase twisted by SiO anchoring, previously discovered (cf. the previous paper) has been studied with polyvinyl alcohol (PVA) anchoring. The unique feature of this novel electrooptic effect in smectic A phases is that it reverses by relaxing when the electric field is removed. For the case of PVA anchoring the reversibility of the effect only occurs near the smectic A-nematic phase transition in the smectic A phase. The temperature region of the reversibility of this effect can be widened with a higher voltage. A comparison with the case of a reversible electrooptic effect in a smectic A with a preceding twisted nematic phase and SiO anchoring is made. The possible application of this electrooptic effect in liquid crystal displays with storage is discussed briefly.