AbstractThree types of transparent PVC‐films before and after exposition in the weather conditions are studied. The first film (the control) is plasticized and stabilized; the second is similar to the first but 1 part of cuprous oxide (CuzO) is incorporated in it, while in the third 1 part of aluminium (A1) powder is added. It is found that the light transparency decreases by 2‐7% upon adding Cu2O and by 17‐36% upon adding Al‐powder. UV‐visible measurements, colourimetric measurements and microscopic investigations are used for examining PVC‐samples properties during weathering. The surface layer chemical changes are studied by means of MIR‐IR‐spectroscopy. The total colour variation (ΔE*ab) in the case of 12 months aged PVC‐film, containing Cu2O, shows 11 relative units in comparison with 37 relative units for the other two materials. A retarding action of Cu2O and an accelerated effect of Al‐powder on the weather degradation of clear soft PVC‐films are established. The influence of the chemical properties and different size distribution of the dispersive additives on photooxidative behaviour of PVC‐compositions are discussed.