Is there a way of placing a validation rule for Field2 based on the value of the same record in Field1 such that the time entered in Field2 must be greater than the time value in Field1?

Yes aziz,

You can refer to other fields inside the validation rule...
just enter as a validation rule:
> [Field1]
And it should work

I tried that and I get the error message

'Invalid SQL syntax - cannot use multiple columns in a column-level CHECK constraint'.

If I create a copy of the table and remove the primary key and place the validation rule in the table properties, it's OK.