Wavelength sensitivity of the photoinduced reaction in polycarbonate

Bisphenol A polycarbonate (PC) was irradiated with monochromatic light of wavelengths 260, 280, 300, 320, 340, 400, and 500 nm by use of the Okazaki large spectrograph (OLS). The quantum yield of main-chain scission (ϕcs), efficiency of photo-Fries rearrangement (Er), and effects of wavelength on ϕcs and Er were investigated. It was found that photodegradation and photo-Fries rearrangement of PC took place by the irradiation of 260–300 nm light, but did not by the irradiation at λ ≧ 320 nm. The ϕcs has a maximum value in the case of the irradiation with 260 nm light, while Er was found to have a maximum value by the irradiation of 280 nm light. © 1993 John Wiley & Sons, Inc.