SQL Server 2014 :: NULL And Empty Strings

I have always (or at least intended to) treat NULL and empty strings separately in my SQL querying history. Now I have run across something that mystifies me (but probably shouldn't) that I would like an explanation for.

Consider this bit o' code:

DECLARE @ORDER CHAR(10)
SET @ORDER=
(
SELECT NULL
)
IF @ORDER <> ''
PRINT 'Not an empty string'

IF @ORDER IS NULL
PRINT 'It is NULL'

Run this and you will get:

It is NULL

I was expecting:

Not an empty string
It is NULL

Why is NULL not passing the 'not an empty string' test? In other words, how does NULL = '' ? Is NULL cast to an empty string for this comparison?