From the variations of the spectral bands, it is suggested that the scission of the phthalazine ring along N-N bond occurs during pyrolysis, leading to the formation of compounds of phenyl with the conjugated nitrile group and the isocyan group. 根据谱带的变化规律,提出了试样在热解炭化时会沿着二氮杂萘环的NN键断裂,形成共轭腈基及异氰基的苯环化合物。