Pyrolysis-GC/mass spectrometry experiments reveal that naphthalene groups attached to maleated polyethylene as the 1-naphthylethyl ester are stable for relatively long periods of time at 170 degrees C. Decomposition can be detected for samples heated for 2.0 min at 200 degrees C, but even at that temperature, the extent of decomposition is very small. At higher temperatures, two of the decomposition products from the labeled polymer are readily understood : 1-vinylnaphthalene and 1-naphthylethanol can form by reactions that are well-precedented in the organic chemistry literature. At 200 degrees C, only naphthalene is formed, which requires scission of the bond between the naphthyl ring and the C-1 carbon of the ethyl group. We suggest two possible pathways for this reaction.