A thin colorless radiochromic diacetylene monomer sensor coated on a transparent polyester base undergoes solid-state polymerization via free radical mechanisms when irradiated with ultraviolet 266 nm wavelength, x- and gamma rays, and high-energy electron beam irradiation. The radiation-induced polymerization reaction leads to the formation of 1, 4-trans additions as polyconjugations along the ladder-like polymer chains.As a result, the colorless, transparent films responds to ultraviolet and to ionizing radiation by turning deep-blue, with an absorption spectrum that exhibits two distinct absorptions. Pulse radiolysis and flash photolysis techniques were used to measure the kinetics of the polymerization propagation reactions. The pulsed-electron- induced propagation of polymerization has an observed first- order rate constant of the order of 103 s-1, followed by much slower blue-shift of the primary absorption band. The activation energy of the polymerization was found to be ≈ 50 kJ mol-1. The fast kinetics of the UV-induced polymerization is faster by about one order of magnitude. The film can be utilized for optoelectronics, remote sensing, and radiation dosimetry.