Thermally imageable elements comprising a masking layer and a substrate are disclosed. The masking layer contains a sulfobetaine and/or a carboxybetaine containing co-polymer or a mixture of a sulfobetaine and/or a carboxybetaine containing co-polymers and absorbs both infrared and ultraviolet radiation. When the masking layer is on the substrate, the imageable element may be imaged and developed to form a photomask. When the imageable element additionally comprises a photosensitive layer, the masking layer may be imaged and developed to form an integral photomask. The imageable elements that comprise a photosensitive layer are useful as flexographic printing plate precursors.