TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The solar module is a film at the back side of the single- or multi-layer film with a thickness of 100-500 pm. The film at the back side of the single- or multi-layer film exhibits at least one layer based on a thermoplastic material with a water vapor diffusion of less than 3 g/m2-d and a glass transition temperature of 60-100 degrees C between at least two layers comprising the components (a)-(d). The composition of the component (c) comprises 5-40 parts by wt., preferably 15-25 parts by wt. based on the sum of the components.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The component (a) is an aromatic polycarbonate and/or an aromatic polyester based on 2,2-bis-(4-hydroxyphenyl)propane.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The component (b) is a graft polymer based on a diene-free rubber, preferably based on a silicone-acrylate-composite rubber. The component (b) comprises (in wt.%): (i) at least one vinyl monomer (5-95 wt.%, preferably 25-50 wt.% based on the total weight of the component (b); and (ii) at least one graft base with a glass transition temperature of less than 10 degrees C, preferably less than -20 degrees C, where the sum of the components (i) and (ii) is made up to 100 wt.%. The component (i) is a mixture of monomers comprising: (iii) vinyl aromatics, ring-substituted vinyl aromatics and/or methacrylic acid-(1-8C)-alkyl esters (50-99 wt.%, preferably 70-80 wt.% based on the total weight of the component (i); and (iv) vinyl cyanides, (meth)acrylic acid-(1-8C)-alkyl esters and/or derivatives of unsaturated carboxylic acids (1-50 wt.%, preferably 20-30 wt.% based on the total weight of the component (i), where the sum of the components (iii) and (iv) is made up to 100 wt.%. The component (c) is a polymer or a copolymer of at least one monomer of vinyl aromatics, ring-substituted vinyl aromatics, vinyl cyanides, (meth)acrylic acid-(1-8C)-alkyl ester, unsaturated carboxylic acids or its derivatives. The component (d) comprises up to 0.01-20 parts by wt. based on the sum of components (a)-(c) in the composition. The component (d) comprises: at least one polymer additive of lubricating- and mold-releasing agents, thermal stabilizers or pigments; and at least one white pigment, preferably titanium dioxide, which comprises 0.5-20 parts by wt., preferably 2-10 parts by wt. based on the sum of the components (a)-(c) in the composition. EXAMPLE - Ethylene vinyl acetate (EVA) film, a crystalline silicon solar cell, an additional EVA film, and finally the back side film comprising (in parts by wt.) polycarbonate (60), Metablen SRK200 (RTM: Styrene-acrylonitrile-grafted silicone-butyl acrylate composite rubber) (20), styrene-acrylonitrile copolymer (20), pentaerythritol tetrastearate (0.5), Irganox B 900 (RTM: Thermal stabilizer) (0.1) and titanium dioxide (7) were subsequently placed on the glass disc (4 mm in thickness). The obtained arrangement was then placed in a vacuum laminator for 26 minutes at 140 degrees C to obtain a laminated solar module.