A1.2.2 Poly(vinyl chloride) compounds undergo complex
changes when exposed to the weather. Color changes are
caused by chemical changes in the PVC, additives, or pigments.
Color changes are caused by selective erosion of some
pigments faster than others. Changes in impact strength are due
to chemical changes in the PVC or additives, or due to physical
changes on the surface as a result of erosion and crazing.