Then the inventors developed a thermosensitive recording medium using a diphenyl sulfone derivative by leaving one of the hydroxyl groups and replacing the other hydroxyl group with {HEAD ~ an alkoxy group} in {TAIL ~ the diphenyl} sulfone derivative  
in
Then the inventors developed a thermosensitive recording medium using a diphenyl sulfone derivative by leaving one of the hydroxyl groups and replacing the other hydroxyl group with { HEAD ~ an alkoxy group } in { TAIL ~ the diphenyl } sulfone derivative
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH