Bootstrap datetime picker in Modal mode not appearing

I am trying to implement a datetime picker of bootstrap in modal view such as this screenshot below:

My code is as follows:

HTML:

<div class="modal-content">
                        <div class="modal-header">
                            <button type="button" class="close" data-dismiss="modal" aria-hidden="true">
                                &times;
                            </button>
                            <h4 class="modal-title" id="H3">Add New Overtime</h4>
                        </div>
                        <div class="modal-body">
                            <div class="form-group">
                                <div class='input-group date' id='ot_date'>
                                    <input type='text' class="form-control datepicker" placeholder="Enter OT Date" />
                                    <span class="input-group-addon"> <span class="glyphicon glyphicon-calendar"></span> </span>
                                </div>
                            </div>

                            <div class="form-group">
                                <div class='input-group date' id='ot_timein'>
                                    <input type='text' class="form-control" placeholder="Enter OT Time-in"/>
                                    <span class="input-group-addon"> <span class="glyphicon glyphicon-time"></span> </span>
                                </div>
                            </div>

                            <div class="form-group">
                                <div class='input-group date' id='ot_timeout'>
                                    <input type='text' class="form-control" placeholder="Enter OT Time-out" />
                                    <span class="input-group-addon"> <span class="glyphicon glyphicon-time"></span> </span>
                                </div>
                            </div>

                        </div>
                        <div class="modal-footer">
                            <button type="button" class="btn btn-default" data-dismiss="modal">
                                Close
                            </button>
                            <button type="submit" class="btn btn-primary">
                                Save
                            </button>
                        </div>

                    </div>

JS:

<script type="text/javascript">
$(document).ready(function() {
    $('#ot_date').datetimepicker();

    $('#ot_timein').datetimepicker({
        language: 'en',
        pick12HourFormat: true
    });

    $('#ot_timeout').datetimepicker({
        language: 'en',
        pick12HourFormat: true
    });
});

I have checked the following links but still no definite answer.

Query1 - DateTime picker in bootstrap is not working

Query 2 - Twitter bootstrap datetime-picker not showing properly in modal

Query 3 - Bootstrap datetime-picker showing in modal as partial