Optical information recording medium using squarylium compounds

An optical information recording medium comprising a substrate, and a recording layer formed on said substrate, which comprises a squarylium compound having formula (I):

• ##STR13## in which R.sup.1 and R.sup.2 independently represent hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group which may have a substituent, or an aralkyl group having 7 to 10 carbon atoms, which may have a substituent;
• R.sup.3 represents a halogen, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a nitro group, or a hydroxyl group;
• n is an integer of 0 to 4 and R.sup.3 s may be the same or different when n is 2 to 4;
• R.sup.4 represents a halogen, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a hydroxyl group, a nitro group, a cyano group, a trifluoromethyl group, or ##STR14## in which R.sup.9 and R.sup.10 are the same as defined in R.sup.1 ;
• p is an integer of 0 to 5 and R.sup.4 s may be the same or different when p is 2 to 5;
• R.sup.5 and R.sup.6 independently represent an alkyl group having 1 to 4 carbon atoms;
• R.sup.7 represents an alkyl group having 1 to 4 carbon atoms, an aryl group which may have a substituent, or an aralkyl group having 7 to 10 carbon atoms, which may have a substituent;
• R.sup.8 represents a halogen, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, an aryl group which may have a substituent, or an aralkyl group having 7 to 10 carbon atoms, which may have a substituent;
• and q is an integer of 0 to 4 and when q is 2 to 4, R.sup.8 s may be the same or different and may form an aromatic ring which may have a substituent, in combination with two adjacent carbon atoms in the ring to which R.sup.8 s are bonded,
• wherein said substituent of said aryl group and said alkaryl group represented by R.sup.1, R.sup.2, R.sup.7, R.sup.8, R.sup.9 or R.sup.10 is selected from the group consisting of halogen, an alkyl group having 1 to 4 carbon atoms, and an alkoxyl group having 1 to 4 carbon atoms;
• and wherein said substituent of said aromatic ring formed by R.sup.8 s is selected from the group consisting of halogen, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and an aryl group.