Sorry for the delay in responding your query.
We have checked your requirement to disable time ranges in Datetimepicker. Sorry but this requirement is currently not feasible with Datetimepicker. So, we have considered the reported scenario as the improvement in Datetimepicker that will be included in any one of our upcoming releases. We appreciate your patience until then.
You could track the status of this feature in our feedback portal tool.
If you have any specific requirement for this feature in your application, please add it as a comment in the above link and we will consider this in the initial implementation phase itself.