It is surprising to me that no one has actually discussed the nature of a fluorescent paint of film. When you understand that, you understand the futility of seeking long life from true fluorescent materials.
To be specific, true fluorescent pigments react to ultraviolet light and "glow". In doing so, the pigments are literally consumed in the process ... hence the normal life of a true fluorescent pigment is 60 to 90 days before a noticeable fade or loss of glow is seen. If you laminate it with a UV inhibiting film, you can extend the life a bit but only to the extent that you reduce the fluorescent effect.
If you need a longer life then you need to look at some of the very bright films from 3M and the like that catch the eye but do not fluoresce.