This is one is not free but it is from the CBOE (and inexpensive in a sense): http://www.marketdataexpress.com/dataSearch.aspx They sell two databases, OPTSUM and Open-Close. If you are intested only in closing prices and volumes/open interest, OPTSUM is the right product. If you want even more detailed information (like the breakdown of the transactions by size and type) then Open-Close is the one to use.
You can subscribe to options software like ONE and they have all the data in 5 minute intervals. The cost is around $70/month, and you also get all the features that come with the software.