Abstract: The invention relates to novel thermochromic spiro heterocyclic compounds having one or the other of the following formulae: ##STR1## where R.sub.1 denotes hydrogen atoms or one or more electron-donor groups in positions 5, 6, 7 and 8 in formula (1); R.sub.i ' denotes hydrogen atoms or one or more electron-donor or electron-acceptor groups in positions 4', 5', 6' and 7' and 4", 5", 6" and 7" in formulae (1) and (2); and R.sub.j denotes hydrogen atoms or one or more electron-donor groups in positions 5, 6, 7, 8, 9 and 10 in formula (2). Use in thermographic recording material.