This invention relates to polymeric optical materials suitable for use in waveguide-based optical touch screen sensors. In particular, the materials should have a glass transition temperature (Tg) below a minimum operating temperature of the touch screen device. Preferably, waveguides composed of the materials are fabricated on polymer substrates, so that the waveguide assembly is flexible. In this case, the materials should have Tg below a Tg of the polymer substrate.