ASPECTS OF PLASTIC SCINTILLATORS .1. BEHAVIOR OF FLUORESCENT MOLECULES IN A POLYMERIZING MEDIUM

The interaction between a number of organic fluors and vinyltoluene during thermally induced polymerization has been investigated by using kinetic and fluorescence techniques. It has been confirmed that 2,5-diphenyloxazole, bis-2(5-phenyloxazoyl)benzene and p-terphenyl do not react in the polymerizing medium and are present in the final product as solute in a solid solution. However, 1,1 prime 4,4 prime -tetraphenyl-1,3-butadiene and 9-methylanthracene do react, via chain-transfer steps. The diene is concentrated in the low mol. wt. tail of a polymer of broad MWD and can be removed by further fractionation. The anthracene species undergoes structural rearrangement with accompanying loss of fluorescence activity during reaction with the growing polymer chains.