When you awaken. Basically rage mode, can do different things for characters i.e at 3 orbs on Ara you go EN mode.
If you socket awakening charge then you get rage quicker from attacks/getting attacked.
On the wiki page,, we've put the ins and outs of socketing equipment, scroll down and you see all the stats and their descriptions including maximums etc.
If you're lazy it's 'Increases your Awakening Charge Speed +x%. (Max: 50%)' for Awk. Charge.
For more info on Awakening itself; http://elwiki.net/w/Awakening_Mode