Polymers containing thermally dissociable and soluble groups and the use of such polymers as organic electroluminescent materials

A polymer, comprising:

• a repeating unit comprising an aromatic ring and a hydrocarbon ring fused to the aromatic ring;
• and
• a thermally dissociable and soluble group which is bonded to the hydrocarbon ring,
• wherein:
• the thermally dissociable and soluble group is a group which is thermally dissociated through a reverse Diels-Alder reaction at 100° C. or more and 300° C. or less, such that the thermally dissociable and soluble group is cleaved from the hydrocarbon ring and the aromatic ring remains in the repeating unit after the thermal dissociation;
• and
• the hydrocarbon ring is a ring comprising a double bond which is not contained in the aromatic ring.