Just send a email which gets straight to the point. Make sure you mention how much you like your job & how the added education will make you a better employee & that added knowledge could be of value to the company you work for. So by giving you the time off will be a "Investment" to both your & the Employers future as your Employer will be able to benefit from a employee who has a degree & this degree could be utilized down the track if you are promoted.
