Wow, what an interesting question for you to ask me lol, as I just had presented this question to the guys over at /r/comicbookcollecting/ here https://www.reddit.com/r/comicbookcollecting/comments/7qc163/golden_age_silver_age_bronze_age_copper_age_who/

Copper Age is right after Bronze, depending on who you are speaking to, the start date of Copper Age can go from 1984, 1985, 1986 to only about 91 where the Modern Age begins OR you have also some who just put Copper Age and Modern Age as the same thing and it runs until now.