I've had strabismus since birth but started treatment for it when I was four. There is no way for anyone to tell you how long it will take to see an improvement in your baby's eye alignment. Every child is different and eyeglasses may not correct the alignment. I was prescribed eyeglasses to treat strabismus and they gave me nasty headaches. My parents and doctor quickly agreed that eyeglasses was not a good treatment option for me. I was also patched, had vision therapy, and two strabismus surgeries. My eye's alignment is better than it was, but I still do not have good binocular vision. The strabismus is still noticeable when I am tired or fatigued. I am not trying to discourage you in any way, I just wanted to let you that each child responds differently to treatment and there is no way to know how your child will respond.
As I know that alignment can not be corrected by wearing prescribed eyeglasses. Regarding to your question, I totally agree with Melissa garcia that every child is different. You need to consult your baby's eye doctor. Hope this helpful.