Glass-Forming Liquid Crystals for Photonic Devices

Glass-forming llquid crystals GLC are a unique class of materials. At room temperature, they are solid and have the properties of a hard plastic. At temperatures above the glass transition temperature they are fluid and behave as a conventional nematic liquid crystal until the temperature exceeds the clearing temperature, at which point a GLC becomes an isotropic fluid. In this program we demonstrated the ability to align a thin film of GLC using an electric field at elevated temperatures and the ability to freeze in the new molecular orientation by allowing the film to cool below the glass transition temperature with the field applied. This is a unique property for an electrooptic material. With such a material, optical devices can be developed that can be electronically set to a desired optical state and latched eliminating the need for continuous electrical power. Such a capability in electrooptic devices would be both unique and highly desirable for several electrooptic applications, such as routing fiber optic signals. Currently available GLC materials are inherently slow because of the liquid crystal moieties used in the molecule. A Phase II program will focus on developing new GLC materials specifically designed for electrooptic applications.