Mixed Wavelength Research Articles

Wavelength effects on the photo-chemistry of poly(vinyl chloride)

The photo-chemical oxidation of poly(vinyl chloride) film has been studied under various conditions of excitation wavelengths. At ‘short’ wavelength (254 nm) under vacuum, two photo-products are observed at 270 and 284 nm. The two photo-products are in photo-chemical equilibrium and accumulate during irradiation. The photo-product which absorbs at 270 nm can be photo-oxidized. Under irradiation at ‘long’ wavelength (365 nm), polyene sequences are formed. Under mixed wavelength radiation (phosphor 310), a combination of these two behaviours occurs and leads to results quite different from those observed under natural conditions of weathering, or under excitation at λ′s > 300 nm in photo-accelerated devices.