END-TO-END CYCLIZATION OF A PYRENE END-CAPPED POLY(BISPHENOL AF-DIETHYLENE GLYCOL CARBONATE) IN SOLUTION

A pyrene end-labelled poly(bisphenol AF-diethylene glycol carbonate) h as been synthesized. Its molecular weight and end-group composition we re determined through a combination of u.v. absorption and fluorescenc e decay measurements of the pyrene end-groups. Through gel permeation chromatography, several fractions were collected. For each fraction, t he cyclization dynamics of the polymer in dilute solutions in acetone and toluene were investigated through studies of intramolecular fluore scent excimer formation. Values for <k(1)>, the end-to-end cyclization rate constant, as well as for k(_1) and k(E) were calculated.