The present invention provides a composition comprising at least one monomer of Formula I, at least one monomer of Formula II, and at least one alkali metal salt of Formula III and/or Formula IV The present invention also provides a process of fabricating a three-dimensional object, comprising i) dispensing a build material that comprises a model material composition and a support material composition; ii) curing the layer dispensed in step i); iii) repeating step i) and ii) so as to sequentially form a plurality of layers in a configured pattern corresponding to the shape of the object; and iv) removing the support material from the build material.