Preparation and characterisation of bifunctional reverse mode polymer-dispersed liquid crystals

Reverse-mode polymer-dispersed liquid crystals (PDLCs) are transparent films in their OFF state (no applied electric field) and become opaque in their ON state. The addition of a photo-chromic compound allows a colour change of films, when they are ultraviolet (UV)-irradiated. The aim of this work was the preparation and characterisation of bifunctional materials, able to change their transparency by application of an electric field and colour under UV irradiation. In particular, the performance of reverse-mode PDLCs doped with different spiro(indolo)-oxazine molecules was investigated. Both the electro-optical and photo-chromic response of these systems were evaluated and compared.