Version: 2017.2
public static Quaternion Slerp (Quaternion a, Quaternion b, float t);

Description

Spherically interpolates between a and b by t. The parameter t is clamped to the range [0, 1].

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour { public Transform from; public Transform to; public float speed = 0.1F; void Update() { transform.rotation = Quaternion.Slerp(from.rotation, to.rotation, Time.time * speed); } }

See Also: Lerp, SlerpUnclamped.