We have evaluated photorefractive effects at 1320-nm and 1064-nm optical wavelengths in interferometric modulators built using Ti-indiffused waveguides in lithium niobate. The sensitivity to photorefractive damage is substantially increased by anneals in non-oxygen atmospheres at temperatures greater-than-or-equal-to 200-degrees-C. The sensitivity can be reduced by an anneal in oxygen. Properly annealed modulators operated for 150 h with 400 mW at 1320 nm with no photorefractive effects other than a 3-degrees change in bias point.