OPTICAL INFORMATION RECORDING MEDIUM

PROBLEM TO BE SOLVED: To obtain an optical information recording medium having degradability when it is allowed to stand in the natural world by using a degradable polymer having at least one of photodegradability and biodegradability as part or all of the material of at least the substrate of a medium with a light interference layer containing a dye phase on the substrate. SOLUTION: The degradable polymer is preferably an ethylene copolymer of formula I, wherein each of (x) and (y) is the number of repeating units on the condition of x+y=100, (X) is 50-99.9, (y) is 0.1-50, X is nitrile or a group of formula II, III or IV and each of R1-R3 is H or 1-3C alkyl. The ethylene copolymer is obtained by copolymerizing ethylene and 2-nitrile-3-vinyloxirane, 2-acetyl-3-vinyloxirane, 2-acetoxy-3-vinyloxirane, 2-acetamide-3-vinyloxirane or the like in the presence of a radical polymerization initiator. A used medium is discarded while suppressing environmental pollution and treatment cost is also reduced.