Makrofol LP 209 polycarbonate, an extruded film, won't discolor when exposed to radiation.
It also meets US-Pharmacopoeia, Class VI and ISO 10993-1 biocompatibility standards for plastics (i.e., withstands 30 days of contact with body fluids). The films come in 175 to 500 m thicknesses with glossy (top and bottom) surfaces. Other thickness and surface structures are available.
Bayer MaterialScience LLC, 100 Bayer Rd., Pittsburgh, PA 15205, (412) 777-2000, bayermaterialsciencenafta.com