The diphenyl sulfone derivatives previously utilized as a color developing agent or an image stabilizer in a thermosensitive color developing layer of a thermosensitive recording medium were mainly the derivatives containing {HEAD ~ hydroxyl groups} in {TAIL ~ both ends} 
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The diphenyl sulfone derivatives previously utilized as a color developing agent or an image stabilizer in a thermosensitive color developing layer of a thermosensitive recording medium were mainly the derivatives containing { HEAD ~ hydroxyl groups } in { TAIL ~ both ends }
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 OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL