A dimethacrylate based on bisphenol-S (DBSMA) was prepared and characterized by Fourier Transform infrared spectroscopy (FTIR), Electrospray Ionisation Tandem Mass Spectrometry (ESI/MS) 1H NMR, and 13C NMR. DBSMA was investigated by a real-time infrared spectroscopy (RTIR), under different conditions such as varying photoinitiator type and concentration, with and without oxygen, mixing with different amounts of a reactive diluent [1,6-hexanediol dimethacrylate (HDDMA)]. The mechanical and thermal properties of these curing films were also investigated by dynamic mechanical analysis and thermogravimetric analysis. The results showed homopolymer of DBSMA has better thermal stability than copolymers of DBSMA/HDDMA systems. Also, the cured DBSMA polymer exhibited higher glass transition temperature (Tg) and better thermal stability compared with commercial available resin 2,2-Bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (BIS-GMA) (CN151). (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013