Provided are compositions which include a polymer, having units of the formula (RSiO1.5), wherein R is a substituted or unsubstituted organic group, and a plurality of functional end groups. A first component is provided for altering the solubility of the composition in a dried state upon activation. A second component contains a plurality of functional groups chosen from epoxides, oxetanes, vinyl ethers and combinations thereof. The second component is present in an effective amount to improve flexibility of the composition in a dried state before and after activation. Also provided are flexible optical waveguides, methods of forming flexible optical waveguides and electronic devices that include a flexible optical waveguide.