Deposition of colloidal silica and silicate based salts on equipment surfaces continue to pose serious challenges to industrial water technologists. Currently, a wide variety of non-polymeric and polymeric additives are used to combat the problems of silica scaling. These additives are generally effective as scale inhibitors and dispersants under normal operating conditions. However, polymeric additives may lose some performance activity under thermal stress. This paper investigates the impact of composition and the influence of thermal stress on the performance of polymeric silica polymerization inhibitors.