Polymer selection criteria for the orbiting wide angle light-collector (OWL) project lens material

Optical quality polymers normally incorporate functional groups that provide physical integrity that are incompatible with deep UV radiation. Groups like the phenyl ring found in polystyrene (PS) increase the refractive index of the polymer, provide a bulky group that inhibits crystallization rendering the material amorphous, and adds impact strength to the polymer by coupling vibrations of the ring into fracture mechanisms. However these groups also absorb UV light at wavelengths starting at about 330 nm or longer repressing ultra-violet transparency. Our search for a polymer with properties similar to polystyrene or poly(methylmethacrylate) but with better ultraviolet transparency led us to study poly(methylpentene) as a potential lens material candidate.