Hi Michael,
By using Gmail account, you can easily export Thunderbird data in MS Outlook with the help of the given steps;
1.) Firstly you need a Gmail account with IMAP enabled.
2.) Now configure your Gmail account in Thunderbird.
3.) For each folder of archived mail you have in your main Thunderbird account, create an identical folder in the Gmail account as that of Thunderbird.
4.) After that copy all Thunderbird folders in Gmail account. Since, the Gmail account is set up to use IMAP, when you copy those emails they are mirrored to your Gmail account. It even preserves the original send date. Make sure the synchronization is complete before you perform step 5.
5.) Now configure Gmail account in MS Outlook 2013 and Download all your emails in Outlook from Gmail.
6.) After that configure main Email account in Outlook 2013 and create your folder.
7.) Copy all messages from Gmail account folders to your main email account folders.
I hope it will work for you.
Thanks & Regards