Chemical defects in molecular chains and the luminescent properties of polystyrene

Absorption and luminescence emission and excitation spectra were studied fo r commercial PS of various origin. Its luminescent properties were found to be primarily due to chemical defects in the main polymer chain and to opti cal impurity centers. Fluorescence of this polymer in the 300-350 nm range is associated with the emission of PS excimers and impurity centers having the structure of styrene and a concentration of 0.3 to 0.03% of that of maj or repeating units in various samples. The fluorescence band at longer wave lengths with maxima at 338, 350, and 370 nm is determined by end groups of phenylhexatriene structure, which appear in the industrial manufacturing or processing of the polymer. The concentration of these groups was estimated at similar to 10(-6) mol/l or lower. The scheme of their formation in PS i s discussed.