Environmental stress cracking (ESC) begins with crazes on the surface of the plastic. Plastic optics may corrode
due to ESC. Usually ductile, plastic may become brittle, and subject to failure due to mechanical, physical, or
chemical influences. Stress cracking is accelerated by temperature cycling, duration, temperature, chemicals,
and cross-linking, orientation, or other characteristics within the plastic. Plastic optics for solar energy conversion
include large-area Fresnel lens parquets commonly used in concentrator photovoltaics (CPV). Solar energy
conversion takes place in a harsh environment. We look for evidence for ESC in plastics and glass optics for
sunlight collection, measure stress, and discuss the possible impact of stress on longevity, optical efficiency, test
methods, and manufacturing strategies.