NOVELTY - The film (200) has a weatherable multilayer optical film layer including coefficient of hygroscopic expansion of less than about 30 parts per million per percent relative humidity. A thin sputter-coated tie layer (140) is provided between the optical film layer and a reflective layer (150). A weatherable layer (220) is placed adjacent to the optical film layer, where the optical film layer exhibits average radiation reflectivity of 90% over a portion of solar radiation wavelength range from 380 to 3000 nanometer. A corrosion protective layer is placed adjacent to the reflective layer.    USE - Solar mirror film for use in a reflector assembly and concentrated photovoltaic system of a concentrated solar power system (all claimed) at industrial plant for long-term outdoor application i.e. solar energy application.    ADVANTAGE - The film allows a block copolymer to be combined with a suitable UV light absorber so as to enhance stability of the film. The film utilizes a copper layer that acts as a sacrificial anode so as to provide a reflective article with enhanced corrosion-resistance and outdoor weatherability, thus improving durability and optical performance of the film. The film eliminates or minimizes stress differential caused by disparity in coefficient of hygroscopic expansion of the weatherable layer and the reflective layer, and minimizes tunneling and/or delamination thus increasing life of the film, decreasing cost of solar power generation and providing faster and wider adoption of valuable form of green energy generation. The film allows a substrate to be sufficiently smooth that texture in the substrate is not transmitted through an adhesive/metal/polymer stack, thus allowing optically accurate film, maintaining physical integrity of the metal reflective layer by eliminating channels for ingress of reactive species that corrodes the metal reflective layer or degrades adhesive, providing controlled and defined stress concentrations within the reflective film-substrate stack and ensuring better adhesion between a polymer layer and a metal reflective surface.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a solar mirror film.    Premask layer (110)    Thin sputter-coated tie layer (140)    Reflective layer (150)    Solar mirror film (200)    Weatherable layer (220)