The resulting mixture is then stirred and optionally heated over a sufficient period of time to bring about {HEAD ~ formation} of {TAIL ~ the dye product} 
of
The resulting mixture is then stirred and optionally heated over a sufficient period of time to bring about { HEAD ~ formation } of { TAIL ~ the dye product }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL