How to get the time difference into another colum?

Question

How to get the time difference into another colum as we need to know the frequencies between the rows.

So provide me the sqlserver query to find the solution

For example the difference between 6.49 and 7.27 is 38 minutes and that 38 minutes should be displayed in another column.

The 3^rd column will be the difference between 7.27 and 7.52 Like that continuosly..