The degradation of low-MW (Mn = 500 g . mol-1) model compounds of pBA and pHEMA were studied under conditions corresponding to the worst-case temperatures and irradiation intensities likely to be experienced by a surface coating exposed to the harsh Australian environment. Vinyl-terminated polymers were compared to their saturated analogues; the terminal vinyl bond was found to be a source of instability which rendered the polymers more susceptible to degradation. The cyclic degradation mechanism derived from degradation of pMMA in our previous publication is also relevant to pBA and pHEMA. In addition, pBA and pHEMA are susceptible to other degradation and crosslinking reactions; crosslinking is particularly rapid in pHEMA exposed to UV radiation. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.