the optical properties of polymethylmethacrylate polymer dispersed liquid crystals

The effect of the addition of polymer liquid crystals as dispersed molecules to polymethylmethacrylate (PMMA) on the optical properties in the UV-visible and near infrared regions is investigated. From transmission, absorption and reflection spectra the absorption coefficient ?(?) and refractive index (n) at angular frequency of radiation (?) have been calculated at room temperature. The values of the optical band gap (Eopt) have been obtained from the direct allowed transitions in k-space. The width of the tails of localized states in the band gap (?E) was evaluated from Urbach edges. Both the parameters (Eopt) and (?E) vary with the mixing ratio of dispersed liquid crystals.