I don't think I have ever heard or seen anything that would work like that on fiberglass. Your only chance may be a somewhat tainted varnish of some sort, that will stick to the fiberglass. Sort of transparent paint...but do as MoeM says, try it before on a piece of scrap, long enough for you to try to bend it after the varnish is dry, to see if it will crack or jump out of the surface.
Good luck.
DF