Contact the manufacturer, they'll know. The sales staff might not, but they'll generally give you contact information for an engineer or someone else who lives and breathes the stuff and loves talking about it. We had some cable specially manufactured for us and ran into some issues with this. Apparently the chemical they used as UV inhibitors in thermoset jackets makes the cable black (hence why so many cables are black), and when other colors were specified, it lost sunlight resistance.
Even if you're not using the cables outdoors or near a window... how are you storing it, is the reel sitting outside, or perhaps near the window of your van? It's an important consideration to make.
