Accession Number:

AD0606057

Title:

RADICAL-MATRIX INTERACTIONS IN LOW TEMPERATURE GLASSES: PHOTO-REVERSIBILITY,

Descriptive Note:

Corporate Author:

AEROSPACE CORP EL SEGUNDO CALIF

Personal Author(s):

Report Date:

1964-09-01

Pagination or Media Count:

9.0

Abstract:

The near UV irradiation of ether andor ethanol glasses at low temperatures 100 25K leads to the formation of trapped ethyl radicals via an excited impurity-solvent interaction. The radicals were observed by electron para magnetic resonance spectroscopy EPR, both during the irradiation and during the post irradiation period. The EPR spectral line shapes of the ethyl radicals changed as a function of time after light extinction and also of temperature during irradiation. Qualitative kinetics of the spectral changes were examined in some detail. In the absence of dissolved oxygen the spectral line shape changes are reversible upon re-irradiation in the presence of oxygen the ethyl radical is irreversibly converted into the RO2 radical at temperatures where the oxygen can appreciably diffuse. The orgins of the spectral changes are discussed in terms of hindered rotational motions and localized phase changes, as well as the postulation of a possible charge transfer complex formation. Photo-reversibility is assumed tto occur via radiationless transitions involving excited states of the impurities. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE