A solvent-less process for producing a transient document which is capable of self-erasing, wherein the solvent-less process includes a) heating and reacting a photochromic compound and a polymer to form a coating composition, and b) coating the coating composition onto an image-receiving side of a transient document substrate, and further an image forming method using the same solvent-less process and including (i) providing a reimageable medium of a substrate and a photochromic material, wherein the medium is capable of exhibiting a color contrast and an absence of the color contrast; (ii) exposing the medium to an imaging light corresponding to a predetermined image to result in an exposed region and a non-exposed region, wherein the color contrast is present between the exposed region and the non-exposed region to allow a temporary image corresponding to the predetermined image to be visible for a visible time; (iii) subjecting the temporary image to an indoor ambient condition for an image erasing time to change the color contrast to the absence of the color contrast to erase the temporary image without using an image erasure device; and (iv) optionally repeating procedures (ii) and (ii) a number of times to result in the medium undergoing a number of additional cycles of temporary image formation and temporary image erasure.