Light Guide Film (What material is Used for it?)

I'm repairing a broken screen for this phone, and I recently threw away the old digitizer/LCD assembly without realizing that it had a light guiding film on it. All of the replacement light guides ship from china so they would take a pretty long time to get here. I was wondering if anyone knew what material was used for a light guide (or something that would disperse the two LED's between this phones three capacitive buttons, throughout all of them).