Curable compositions include at least one polydiorganosiloxane with at least two hydroxysilyl moieties, at least one hydroxyl-functional polyorganosiloxane resin, and at least one photoactivatable composition that, upon exposure to radiation, generates at least one base selected from amidines, guanidines, phosphazenes, proazaphosphatranes. The curable compositions can be coated on substrates and cured to form coatings, including pressure sensitive adhesives.