These dyes are suitable for use in thermographic imaging systems wherein the leuco dye is in {HEAD ~ a composition} containing {TAIL ~ a nitrate salt} 
containing
These dyes are suitable for use in thermographic imaging systems wherein the leuco dye is in { HEAD ~ a composition } containing { TAIL ~ a nitrate salt }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL