Chameleon is probably the worse line you could possible put onto a spinning reel. It's very stiff, has lots of memory, and has horrible breaking strength compared to similar diameter lines.
I personally like Berkley Big Game, but P-Line and Stren also get very good reviews.
Also exposure to the sun will take it's toll on any line. The UV Rays can really weather the line, although I've never experienced anything like you said. I've only noticed it if I leave a setup out in the sun for awhile.