Solar Radiation
Physical changes resulting from exposure to the environment are initiated by chemical bond breaking reactions caused by the absorbed light, either through direct or indirect processes. Chemical bond breaking is a prerequisite to any chemical reaction, and chemical reactions are a prerequisite to observable or measurable physical changes. Other weather factors mainly promote weathering through their influence on the secondary reactions which follow the breaking of bonds. Degradation of most materials exposed to outdoor conditions is caused mainly by UV degradation -- the ultraviolet portion of solar energy, with the shortest wavelengths often having the greatest effect. Therefore, variations in both the quantity and quality of ultraviolet in both the direct solar beam and diffuse sky radiation are important factors in the design and evaluation of weathering tests.
Read more about this topic: Factors Of Polymer Weathering
Famous quotes containing the words solar and/or radiation:
“Senta: These boats, sir, what are they for?
Hamar: They are solar boats for Pharaoh to use after his death. They’re the means by which Pharaoh will journey across the skies with the sun, with the god Horus. Each day they will sail from east to west, and each night Pharaoh will return to the east by the river which runs underneath the earth.”
—William Faulkner (1897–1962)
“There are no accidents, only nature throwing her weight around. Even the bomb merely releases energy that nature has put there. Nuclear war would be just a spark in the grandeur of space. Nor can radiation “alter” nature: she will absorb it all. After the bomb, nature will pick up the cards we have spilled, shuffle them, and begin her game again.”
—Camille Paglia (b. 1947)