Oracle XE 11.2 Export / Import Charset
The export utility will use the NLS_LANG environment variable specified for the client session.  If all your data can be represented in the Windows-1252 character set, that shouldn't be an issue.  If you want to do the export using the AL32UTF8 character set, you'd need to set the NLS_LANG.  In Windows, that would be something like

c:\&gt; set nls_lang = american_america.al32utf8