If only time value is provided in a data and time literal, the SQL Server will pad the date value with a zero, representing the base date, January 1, 1900. The tutorial exercise below gives you some good examples:

-- 'hh:mi:ss.mmm' format

DECLARE @x DATETIME;

SET @x = '22:55:07.233';

SELECT @x;

GO

1900-01-01 22:55:07.233

-- 'hh:mi:ss.mmmAM/PM' format

DECLARE @x DATETIME;

SET @x = '10:55:07.233PM';

SELECT @x;

GO

1900-01-01 22:55:07.233

-- 'hh:miAM/PM' format

DECLARE @x DATETIME;

SET @x = '10:55PM';

SELECT @x;

GO

1900-01-01 22:55:00.000