Matt, I believe that the mechanical life of a sail will be over due to chafe and general usage/handling/mis-handling before outgassing at 100degF (37degC) becomes an issue. How much the sail is used is a very important part of the equation of course.
We 'always' store our sails in our white painted trailer, and have not had noticed any ill effect?
Do you happen to have any references to literature on the subject (I would like to read more)? I have only read about outgassing tests for vectran, and they started testing at 120degC.