Sudha,
You do indeed need to find the root cause.
If you are paying the best salaries in town, then the teachers have no need to look elsewhere and are just turning up for the pay, working the mandated hours, and leaving. Why wouldn't they? Sounds like they've got a good life and want for nothing. Also, why do they need to stay after 4.30pm if their teaching day is finished?
You have said yourself that they are "not interested in attending training programs". So why are you embarking on a training program? It will be a waste of time, money and energy. I can tell you now they will just sit there passively and contribute nothing. They may even be disruptive in the class, just to show you that they do not want to be there. If you are not skilled in training, then good luck with that. You will have a miserable time.
For training to be successful, the participants HAVE TO WANT TO BE THERE. I am sure that among the CiteHR membership, there are many of us (me included) who have had to attend training we hated and tried to find an excuse not to attend.
I can assure you that "motivational training" is top of the list for most hated training the world over because so much of it is meaningless drivel. I am a trainer and I saw this over and over again. The most important ingredient of training - WIIFM - Whats In It for ME.
It seems to me that you first need to find out what the problems are - then find a fix. It may be that you need to bring an independent person in from outside to run one on one interviews, focus groups etc, to try and determine what the teachers like (other than pay) and dislike about the place. I feel sure there is more to this story than you have told us.