The key difference between Record of the Year and Song of the Year awards at the Grammys is that the Song of the Year award is for the songwriter who composed the song. Unlike the Record of the Year, which is awarded to the entire team involved in producing the song, Song of the Year is for an individual contributor - the songwriter - and is awarded for the lyrical beauty of the song.
Another point to note is that Record of the Year and Album of the Year are different. While Record of the Year is for a single song, Album of the Year is for an entire album.
"Record Of The Year vs Song Of The Year." Diffen.com. Diffen LLC, n.d. Web. 17 Sep 2014. < http://www.diffen.com/difference/Record_Of_The_Year_vs_Song_Of_The_Year >