Embodiments in accordance with the present invention encompass compositions encompassing a procatalyst, a photoacid generator, a photosensitizer and one or more monomers which undergo vinyl addition polymerization when said composition is exposed to suitable UV irradiation and heated to a temperature from 50° C. to 100° C. to form a substantially transparent film. The monomers employed therein have a range of refractive index from 1.4 to 1.6 and thus these compositions can be tailored to form transparent films of varied refractive indices. Accordingly, compositions of this invention are useful in various opto-electronic applications, including as coatings, encapsulants, fillers, leveling agents, among others.