The invention provides organic optical waveguide devices which are lithographically formed and employ polymeric materials having low optical loss, good long term and short term stability, good flexibility and reduced stress or crack induced scattering loss. An optical element has a substrate; a patterned, light transmissive core composition on the surface of the substrate; and a light reflecting cladding composition on the pattern of the core. The core composition has a glass transition temperature of about 80° C. or less and the cladding composition has a glass transition temperature of about 60° C. or less.