Beeber, Ralph2022-06-222022-06-22196713720317https://hdl.handle.net/10657/9862A spectroscopic and photochemical study of 2,7' dimethylbianthrone and 4,5' dimethylbianthrone was carried out. Absorption and emission spectra are reported for 2,7' dimethylbianthrone, 4,5' dimethylbianthrone, 3,6' dimethylhelianthrone, 3,6' dimethylmesonaphthobianthrone, and the photochromic form of 2,7' dimethylbianthrone. The photochemistry of 2,7' dimethylbianthrone was extensively studied. A free radical mechanism is proposed in which the initial reactive species is an excited state of the photochromic form of bianthrone and a secondary reactive species is the photocyclized helianthrone. The influence of the viscosity and steric effects of rigid glasses on the spectra and photochemistry is also considered.application/pdfenThis item is protected by copyright but is made available here under a claim of fair use (17 U.S.C. Section 107) for non-profit research and educational purposes. Users of this work assume the responsibility for determining copyright status prior to reusing, publishing, or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires express permission of the copyright holder.Thesisreformatted digital