Radioluminescence of methylcyclohexane in the glassy state

Thermoluminescent Charge Recombination in Saturated Hydrocarbons

“…The time dependence of the delayed isothermal recombination luminescence of squalane glass was studied with TMPD replaced with 10 -4 M perylene. Following a single intense 308 nm laser pulse at 77 K, the luminescence was found to follow a t - a dependence with a = 1.05 over a time interval ranging from t = 100−10000 s. Such power law dependence has been previously observed in similar systems − ,− and attributed to tunneling of a trapped electron to its sibling cation, with an exponential distribution of initial electron cation separation distances. In this case, a-1, has the simple interpretation as the ratio of the distance parameter in an assumed exponential form for the tunneling probability, to the average initial separation distance of the geminate pair.…”

“…A similarly narrow thermoluminescence spectrum has also been reported in 3-methylpentane glass 31 where again the peak temperature is very close to the glass transition temperature. Although we were unable to obtain a spectrum in the methylcyclohexane glass (see section III), others claim to have done so and report a spectrum that appears to be of the same narrow, distinctive shape. , …”

“…Low energy electrons produced by ionization can become trapped in nonpolar glasses. − The physical properties of trapped electrons reflect the excess electron−solvent interactions that are of fundamental and practical interest regarding ionization in amorphous condensed phases. A number of experimental methods have been applied to elucidate the properties of electrons trapped in nonpolar glasses, including absorption spectroscopy, − photoconductivity, ,− various forms of magnetic resonance, ,,, isothermal recombination luminescence, − and the effects of electron scavengers. − ,,,, Complementary to these methods is the technique of thermoluminescence, to which we confine our focus.…”

“…Thermoluminescence peaks in glasses have been correlated with phase transitions, ,,,, particularly the glass transition at which anion mobility becomes possible. Thermoluminescence spectra frequently supplement studies of isothermal recombination luminescence, − , and have facilitated observation of a number of novel emission processes 30,32,35,36 (cation−anion recombination, excimers, dimers, radicals, enhanced phosphorescence).…”

“…Although we were unable to obtain a spectrum in the methylcyclohexane glass (see section III), others claim to have done so and report a spectrum that appears to be of the same narrow, distinctive shape. 15,16 (55) Wang, H. Y.; Willard, J. E. J. Chem. Phys.…”