Volume 9, Number 1
May 1996

Chemiluminescence: A Technique for Early Determination of Oxidation in Organic Materials

Reprinted with permission from Atlas Sunspots, v. 26 Issue 52, 1st Quarter 1996, p. 1-5, where it appeared under the title "Applications of Chemiluminescence to Thermal and Photooxidative Stability of Polymers and Other Hydrocarbons."

Chemiluminescence (CL) is light emission (luminescence) generated by a chemical reaction having sufficient energy to produce an excited electronic or vibrational state from which some of the energy is emitted as light. It is a generally accepted fact that oxidation reactions of most organic materials, including polymers, are accompanied by weak emission of light due to release of energy from the carbonyl groups formed in an excited (triplet) electronic state during oxidation. Reactions with oxygen constitute one of the major pathways of deterioration of polymers.

The simplicity and extreme sensitivity of the CL technique in detecting oxidation reactions makes it a valuable tool for determining the extent and nature of thermal and photooxidation in polymers at very early stages and under conditions approaching those in service. CL can detect oxidative degradation long before deterioration is manifested in any physically measurable quantity. In addition to the speed of testing using CL, it has been shown to provide information which could not be obtained from oven tests, infrared spectrometry (IR), oxygen uptake and differential scanning calorimetry (DSC) methods. Detection of changes during initiation states of degradation provides important information on the oxidative stability of materials as well as the mode of action and effectiveness of stabilizers.

[This is an excerpt. The article continues with nine short reports of materials investigated by chemiluminescence, comparing results with those obtained by other methods (including oven tests, IR or UV/VIS spectroscopy, ATR-IR and XPS, and gel permeation analysis). For the full text, call the Atlas Marketing Department in Chicago at 312/327-4528 (fax 312/327-5787).-Ed.]