Abstract: Optical fiber buffer coatings with a low glass transition temperature are prepared from acrylated urethane oligomers having a molecular weight of 2,000 and 6,000, an aliphatic monofunctional acrylate or monofunctional aryl-containing acrylate having glass transition temperatures below -20.degree. C., a photoinitiator, and optionally a crosslinking acrylate ester having at least two acrylate or methacrylate groups per molecule and having a molecular weight less than 4,000. These buffer coatings are flexible at low temperatures, such as -60.degree. C., and avoid microbending, resist water absorption, and have low hydrogen generation.