Unity 3D Rotate from to over time coroutine example

// Untested !

IEnumerator RotateFromTo (Transform t, Quaternion from, Quaternion to, float duration)
{
    float startTime = Time.time;
    float endTime = startTime + duration;



    while (Time.time < endTime)
    {
        float i = Mathf.InverseLerp(startTime, endTime, Time.time);
        t.rotation = Quaternion.Slerp(from, to, i);
    }

}

IEnumerator RotateTo (Transform t, Quaternion to, float duration)
{
    RotateFromTo(t, t.rotation, to, duration);
}