residues as primary product,
which, in turn, may cross-link. Similarly, the carbonyl groups and amide groups resulting from the photo-oxidation at the peptide backbone carbon may establish
Fig. 1. Variation of (a) o-Ps lifetime s3 (free volume hole size Vf), (b) o-Ps intensity I3, and (c) fractional free volume Fv as a function of UV exposure time for virgin hair sample.