Highly transparent and oriented films of the diacetylene monomer, 5,7-dodecadiyne-1,12-bis(n-butoxycarbonylmethylurethane) (4BCMU) in ultra-high molecular weight polyethylene (UHMW PE) were prepared utilizing the gel processing technique wit subsequent tensile drawing. After UV radiation the films yield highly absorbing and oriented poly 4BMCU. The orientation of the polymerized 4BCMU form was investigated using polarized UV-vis spectroscopy and wide-angle X-ray diffraction. Morphology studies showed that 4BCMU crystalized from the melt within the microchannels, with the monomer long axis perpendicular to the internal surfaces and therefore with the polymer axis parallel to the drawing direction. Thermal annealing and the transition to the red form of the films results in a five- to six-fold increase in optical anisotropy. The described system combines several useful security features such as photopatterning, easily detectable optical anisotropy and irreversible color change upon heating, which could be utilized in optical security devices.