Two federal agencies, the Drug Enforcement Administration and the Food and Drug Administration, determine which substances are added to or removed from the various schedules, although the statute passed by Congress created the initial listing.
Polycarbonate is a versatile, tough plastic used for a variety of applications, from bulletproof windows to compact disks (CDs). The main advantage of this material over other types of plastic is its great strength combined with light weight. While acrylic is 17% stronger than glass, polycarbonate is nearly unbreakable.
Polycarbonate is known for its very high impact resistance and for the ability to perform over a wide range of temperatures (-137 to +124 oC). Polycarbonate is similar to polystyrene in index (@588nm, 1.586) and Abbe number (29.9). Because of its high ductility, polycarbonate optics are not easily machined. The resin is more expensive than acrylic. Cyclic Olefin Polymer (COP) is a family of plastic resins with low native stress bi-refringence properties.