Pyroelectric alternate-layer Langmuir-Blodgett films of tricos-22-enoic acid and 1-docosylamme have been polymerised by ultravoilet irradiation. Partially polymerised films retained a significant proportion of the initial Pyroelectric activity. However, irradiation for long periods of time resulted in decarboxylation and photodesorption, which eventually led to the loss of the pyroelectric response.