A method of determining the composition of a polymeric body includes applying electromagnetic radiation to the polymeric body, modulating the electromagnetic radiation using a tagant disposed within a polymer composition forming the polymeric body, and receiving the modulated electromagnetic radiation from the tagant at an infrared detector. The electromagnetic radiation received from the tagant has a signature corresponding to the polymer composition forming the polymeric body. A method of making a polymeric body and system for determining composition of a polymeric body are also described.