To get yourself into the groove of batching, try blocking out two to three daily email check-in times on your calendar, perhaps 30 minutes a piece. If at all possible, schedule an additional 45-90 minutes for creative work before you check your email for the first time. Then, when you do turn your attention to your inbox, no matter what you find there—what fires you have to put out, what unwanted questions you have to respond to—you’ve already gotten some good work done that day.

— Don’t Let Email Zombies Eat Up Your Day by 99U

I've been using Quitter as well to automatically close my email client after a period of time. Out of sight, out of mind and all that.