At the event of a singularity, time doesn't exist... as a matter of fact... neither does space. If u were standing on the event horizon of a singularity,
so i'd say before the big bang the concept of time had no meaning... i mean to say, mass gives time its essence; no mass: no time.
of course the rapid inflationary model of the bigbang is more accepted... but this gives similar consequences.
there's another theory that says that before the BB, Mass itself didn't exist and that the universe wasn't a point. Basically the entire energy in the universe is 0... positive by virtue of mass... and negative energy by virtue of gravity. So when mass was spontaneously created at the BB, it maved avaw in order for the total energy to be )... so in effect; no time there too.