The influence of thermoluminescence on stress-induced chemiluminescence measurements of injection moulded polyamide 66 and polypropylene

During a study of chemiluminescence (CL) emitted during tensile testing of polyamide, some of the samples showed large amounts of additional luminescence. This luminescence was shown to be due to irradiation from fluorescent tubes in a desk lamp and in the laboratory ceiling lamps. A clear bend in the decay curve of the luminescence indicates at least two different luminescence phenomena. The first part of the curve shows fast decay of very intense luminescence. This is proposed to be phosphorescence from direct excitation. The second part of the curve shows much slower decay with lower intensity and is proposed to originate from recombination of trapped charges (thermoluminescence). The thermoluminescence from a specimen was found to be affected by mechanical load. By application of mechanical energy separated charges in the specimen could recombine. The decay of phosphorescence was unaffected by load. ©