transition.to doesn't seem to support color transitions. So I made one myself using enterFrame, which is how I suspect corona's transition library works too.
transition
This function returns a matrix of RGB values that allow you to gradually change from one color to another using a single index, like the position of a scrollview/springboard.
It takes a two dimensional array of RGB colors, each page width and the total amount of pages.
Project for the Moving Objects Along a Path tutorial at: http://coronalabs.com/blog/2014/01/07/tutorial-moving-objects-along-a-path/
A drop-in replacement easing curve for transition.to animations, based on a damped spring.