The dimensional stability of a UV printed polymer microstructure for a novel glazing system for seasonal regulation and daylighting based on a periodic array of parabolic micro-mirrors is investigated. The objectives of the work are: i) to analyze the dimensional changes of UV-printed microstructures related to polymerization and thermal aging; and ii) to identify the impact of these changes on the optical properties of the system. The period was found to be stable, with shrinkage below 1.5% after printing, independent of PI concentration, and remained constant upon thermal exposure. In contrast, dimension W1/2 decreased by up to 14.5% with time at 80°C, presumably due to physical aging processes. A change of height also occurred, but it was partly compensated by the change of W1/2 as a result of Poisson's effects and a complex distribution of internal stress. The impacts of these dimensional changes on the redirection of daylight were also investigated.