script: turn object gradually to a desired rotation

Something like:

   scalingFactor = 1; // Bigger for slower
   transform.rotation = Quaternion.Slerp(transform.rotation, Quaternion.identity, Time.deltaTime/scalingFactor);

 using UnityEngine;
 using System.Collections;
 
 public class Resetter : MonoBehaviour {
 
     System.Random rnd;
     bool running=false;
     // Use this for initialization
     void Start () {
         rnd=new System.Random((int)(Time.time*100));
     }
     
     // Update is called once per frame
     void Update () {
     
     }
     
     void OnGUI()
     {
         if (!running){
             if (GUI.Button (new Rect(10, 10, 100, 100), "Then Hit me")){
                 StartCoroutine(ZeroMeOut(5));
             }
             if (GUI.Button (new Rect(200, 200, 100, 100), "Hit me First")){
                 transform.Rotate(new Vector3(rnd.Next(90), rnd.Next(90), rnd.Next(90)));
             }
         }
         GUI.Label (new Rect(200, 10, 100, 100), "("+((int)transform.rotation.eulerAngles.x)+", "+((int)transform.rotation.eulerAngles.y)+", "+((int)transform.rotation.eulerAngles.z)+" )");
     }
     
     
     private IEnumerator ZeroMeOut(float timeInSeconds)
     {
         running=true;
         Vector3 startRot = transform.rotation.eulerAngles;
         float startTime=Time.time;
         do{
             float lerpValue = (Time.time-startTime)/timeInSeconds;
             transform.rotation=Quaternion.Euler(
                 new Vector3(
                 Mathf.Lerp(startRot.x, 0, lerpValue),
                 Mathf.Lerp(startRot.y, 0, lerpValue),
                 Mathf.Lerp(startRot.z, 0, lerpValue)));
             yield return 0;
         }
         while (Time.time<startTime+timeInSeconds);
         //transform.rotation=Quaternion.Euler(Vector3.zero);
         running=false;
     }
 }