How do I convert .docx or .doc files to XML format just like converting from Word 2003?

It needs to be automatically converted into a document

A quick solution with PowerShell script but VBA macro should work too or another language for coding.

$docxFiles = Get-ChildItem -Path "c:\temp" -Filter '*.doc'

$word = New-Object -ComObject Word.Application
$word.Visible = $false

foreach ($docxFile in $docxFiles) {
     $document = $word.Documents.Open($docxFile.FullName)

     $xmlFilePath = [System.IO.Path]::ChangeExtension($docxFile.FullName, 'xml')

     $document.SaveAs($xmlFilePath, 10)

     $document.Close()
}

$word.Quit()