Thermal broadening of optical homogeneous linewidths in organic glasses and polymers studied via photochemical hole-burning

Photochemical hole-burning was used to study optical dephasing in the S₁ ← S_o OO transitions of dimethyl-s-tetrazine, chlorin and free-base porphin in several organic glasses and polymers. The homogeneous width (Γ_hom) seems to follow a T^1.3±0.1 law between 0.4 and 20 K for all guest—host pairs, and extrapolates the lifetime-limited values of each guest for T→0. For a given temperature, Γ_hom, appears to be related to the number of OH groups in the glass, and to the size of side-groups on the polymer chain.