Photophysics and photochemistry of singlet oxygen in macromolecular matrices
- Sandia National Labs., Albuquerque, NM (United States)
- New Mexico Univ., Albuquerque, NM (United States). Dept. of Chemistry
We are studying the kinetics of singlet oxygen ({sup 1}{Delta}{sub g}O{sub 2}) in solid polymers by monitoring its phosphorescence in time-resolved experiments. In macromolecular matrices where {sup 1}{Delta}{sub g}O{sub 2} is produced by energy transfer from a photosensitizer, {sup 1}{Delta}{sub g}O{sub 2} lifetimes can be obtained by deconvoluting the {sup 1}{Delta}{sub g}O{sub 2} sensitizer kinetics from the {sup 1}{Delta}{sub g}O{sub 2} phosphorescence signal. The sensitizer kinetics can be obtained in a flash absorption experiment. These time-resolved techniques have been utilized to examine the interaction of {sup 1}{Delta}{sub g}O{sub 2} in polymers with two types of additives: (1) molecules capable of undergoing chemical reactions with {sup 1}{Delta}{sub g}O{sub 2} (reactive quenchers) and (2) molecules capable of quenching {sup 1}{Delta}{sub g}O{sub 2} to its ground triplet state (physical quenchers). From this study we have determined directly that significant reactive and physical quenching of {sup 1}{Delta}{sub g}O{sub 2} are possible in a solid polymer. The polymer matrix greatly reduces the quenching rate of a very efficient quencher and slightly elevates the quenching rate of inefficient quenchers, as compared with rates determined in analogous liquids. This compressed range of quenching efficiencies has implications for understanding photodegradation and stabilization of polymers. 12 refs., 3 figs., 1 tab.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- DOE; NSF; USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6045103
- Report Number(s):
- SAND-91-2729C; CONF-920444--4; ON: DE92003955; CNN: CHE-8821324
- Country of Publication:
- United States
- Language:
- English
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