HfO2/SiO2 Brewster's angle polarizers are being developed at Lawrence Livermore National Laboratory for the National Ignition Facility. Damage threshold studies using a 3-ns pulse length 1064-nm laser have revealed a number of different damage morphologies such as nodular ejection pits, plasma scalds, and overcoat delaminations. Of these laser damage morphologies, delaminations have the most negative impact on fusion laser performance. By increasing the thickness of the SiO2 overcoat, the delamination morphology is eliminated without significantly modifying the spectral characteristics of the coating. A model of the thermal mechanical response of the overcoats is presented for various SIO2 overcoat thicknesses. The overcoat thickness influences the electric-field profile resulting in different thermal gradients between the outer SiO2 and HfO2 layers. This modeling effort attempts to understand the relationship between the thermal stress distribution in the overcoat and the occurrence of delamination.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.