Photodegradation of poly(ethylene 2,6‐naphthalate) films

Poly(ethylene 2,6-Naphthalate) films were irradiated in air by various light sources. By means of a spectral irradiator and a UV carbon arc, the most effective wavelength was determined as about 382 mμ. For a wavelength shorter than 375 mμ, the insolubilization reaction occurs only at the surface layer, while at 382 mμ, the chain scission and insolubilization occur at the same time throughout the depth. Some observations on the change of the fluorescence spectra upon UV irradiation are described.