I am a part-time junior software developer for a small company for a little more than 2 years now. I'm still a student, which means, during my semester, I work 20-30 hours a week, but for the past years, both of the summers I were on full-time (40hr/week). I started college in Computer Science 1 year into the job, I was full-time before that.
When I was recruited as a junior with zero-to-little programming experience (only ~1 year self taught, no college), my salary increases were tied to performance "checkmarks" and official, international exams (set by my supervisors). I always had 2-3 months to complete each step, and I usually did it in 1-2 months (always about 3-6 weeks early). Of course, my salary increases were also tied to this.
As a result, since I don't want to leave this job (yet), I thought I would do Google Summer of Code this year, as I am still a college student, and I would benefit from it greatly. This would not be possible if I went full-time.
How do I tell my boss I don't want to switch back to full-time for the summer?